Adhesive sheet, laminate using the adhesive sheet, method for producing the same, and method for producing an article

Abstract

To provide an adhesive sheet which can be bonded without being restricted by light transmittance and heat resistance of an adhesive body, has high following adhesion to an adhesive surface, and can suppress generation of burrs and peeling from the adhesive surface in dicing processing, and to provide a laminate using the adhesive sheet, a method for manufacturing the adhesive sheet, and a method for manufacturing an article.SOLUTION: The invention provides an adhesive sheet which includes an adhesive layer including: photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond; thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond; a photopolymerization initiator (C); and a filler (D), where content of the filler in the adhesive layer is within a predetermined range.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive sheet that can be suitably used for bonding members constituting a laminate in dicing processing.

Background Art

[0002] In recent years, with the miniaturization of electronic devices, components mounted on electronic devices such as semiconductor chips, for example, have been miniaturized so as to be mounted at high density. Since it is troublesome to manufacture small components individually, a multi-sided attachment body in which components such as semiconductor elements are multi-sidedly attached on a single substrate is produced, and the multi-sided attachment body is diced (cut) to be separated into individual pieces, thereby being mass-produced at once.

[0003] As a method of joining members, there is a method using a paste-type adhesive (see Patent Document 1). However, the paste-type adhesive requires adjustment of thickness and management of coating amount during coating, and also requires a cleaning process after coating. Depending on the type of member, cleaning may not be possible, so its application is limited.

[0004] On the other hand, as a joining method alternative to an adhesive, there is a method of joining members using an adhesive sheet (see Patent Document 2). According to this method, for example, one member (first member) can be bonded to one side of an adhesive sheet having a desired thickness, and a plurality of members (second members) can be bonded to the other side. Since the interval between the first member and the plurality of second members is uniquely determined by the thickness of the adhesive sheet, thickness adjustment becomes easy, and adjustment of coating amount and cleaning are also unnecessary, and the joining operation can be simplified.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when joining members using a photocurable adhesive sheet, it is necessary to prepare a laminate by bringing the members into contact with the adhesive sheet in advance before irradiating light, and irradiate the laminate with light through the members to advance the curing reaction of the adhesive sheet. However, in order to irradiate the adhesive sheet with sufficient light to cause a curing reaction, light transmissivity of the members is required. For example, members having a metal surface on the surface, such as metal members or members on which metal parts are placed, have low light transmissivity or do not transmit light, so joining by the above-described method is difficult. Similarly, when joining members using a thermosetting adhesive sheet, it is necessary to heat and press at a high temperature in order to sufficiently advance the curing reaction. However, this method cannot be applied to joining members with low heat resistance, and heat deterioration, damage, and functional degradation of the members and parts occur due to heating and pressing. In addition, there are problems such as strain, deformation between members due to differences in thermal expansion of each member, and cracks occurring between the adhesive sheet and the members, resulting in peeling.

[0007] In addition, in the manufacture of multi-sided bodies, in order to firmly join the members, follow-up adhesion of the adhesive sheet to the adherend surface of the members is required. However, in photocurable or thermosetting adhesive sheets, curing rapidly progresses immediately after light irradiation or heating, so flexibility is impaired in a short time, and particularly, follow-up adhesion to an adherend surface having a step is poor. Therefore, during dicing, the adhesive sheet is likely to peel off from the adherend surface of the member. On the other hand, if the flexibility of the adhesive sheet before and after curing is increased too much to improve the follow-up adhesion to the adherend surface, the cured adhesive layer is likely to soften due to frictional heat during dicing, resulting in burrs. For this reason, in small parts obtained by dicing, there is a problem that the bonding strength between members decreases and the performance of the parts deteriorates due to burrs.

[0008] The present disclosure has been made in view of the above problems, and provides an adhesive sheet that can be joined without being restricted by the light transmittance or heat resistance of the adherend, has high follow-up adhesion to the adherend surface, and can suppress the generation of burrs and peeling from the adherend surface during dicing, a laminate using the same, a method for manufacturing the same, and a method for manufacturing an article.

Means for Solving the Problems

[0009] The present invention provides an adhesive sheet including an adhesive layer containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photoinitiator (C), and a filler (D), wherein the content of the filler in the adhesive layer is 5% by mass or more and 45% by mass or less.

[0010] The present invention also provides a laminate having the above-described adhesive sheet, a first member bonded to the first main surface of the adhesive sheet, and a second member bonded to the second main surface of the adhesive sheet.

[0011] The present invention also provides a method for manufacturing a laminate using the above-described adhesive sheet, the method including: step [1] of bonding a first member to the first main surface of the adhesive sheet; step [2] of bonding a second member to the second main surface of the adhesive sheet; and step [3] of curing the adhesive layer of the adhesive sheet, and further including a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays before step [1] or between step [1] and step [2].

[0012] The present invention also provides a method for manufacturing an article using the above-described adhesive sheet, the method including: a step [1] of bonding a first member to a first main surface of the adhesive sheet; a step [2] of bonding a second member to a second main surface of the adhesive sheet; a step [3] of curing the adhesive layer of the adhesive sheet to form a laminate; and a step [4] of cutting the laminate into a plurality of articles. Further, before the step [1] or between the step [1] and the step [2], the method includes a step of irradiating an active energy ray onto the first main surface or the second main surface of the adhesive sheet.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide an adhesive sheet that can be joined without being limited by the light transmittance or heat resistance of an adherend, has high follow-up adhesion to the adherend surface, and can suppress the generation of burrs and peeling from the adherend surface during dicing; a laminate using the same and a method for manufacturing the same; and a method for manufacturing an article.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, the adhesive sheet of the present invention, a laminate using the same and a method for manufacturing the same, and a method for manufacturing an article will be described.

[0015] 1. Adhesive Sheet The adhesive sheet of the present invention includes an adhesive layer containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and a filler (D), and the content of the filler (D) in the adhesive layer is within a predetermined range.

[0016] The adhesive sheet of the present invention can be joined without being limited by the light transmittance or heat resistance of an adherend, has high follow-up adhesion to the adherend surface, and can suppress the generation of burrs and peeling from the adherend surface during dicing.

[0017] Specifically, in the adhesive sheet of the present invention, since the adhesive layer contains desired components, the curing reaction rate after light irradiation is slow and the reaction proceeds gradually. Therefore, when joining members, the adhesive sheet of the present invention can irradiate light in advance to cause a curing reaction of the adhesive layer, and the members can be bonded as long as the curing reaction is not completed. As a result, unlike ordinary photocurable or thermosetting adhesive sheets, in a state where the members to be joined are laminated via the adhesive sheet, the curing reaction proceeds without irradiating light or heating and pressurizing at a high temperature. Therefore, the members can be easily and firmly joined without being restricted by the light transmittance and heat resistance of the adherend.

[0018] Further, in the adhesive sheet of the present invention, since the adhesive layer contains desired components, the curing reaction does not proceed rapidly after light irradiation but proceeds gradually, so it can have flexibility even after light irradiation. Therefore, in the adhesive sheet of the present invention, during the process of curing the adhesive layer, it can follow and adhere closely to the adherend surface, particularly the steps on the adherend surface. Further, since it has appropriate flexibility even after curing, it can exhibit a high adhesive force to the members.

[0019] Furthermore, in the adhesive sheet of the present invention, since the adhesive layer has a composition containing a desired amount of filler, while having appropriate flexibility after curing and ensuring adhesion to the adherend surface, when dicing the laminate formed by joining members via the adhesive sheet of the present invention into individual pieces, the cured adhesive layer receiving frictional heat can be suppressed from softening and stretching, and can be made more likely to break. As a result, the generation of burrs and peeling from the adherend surface can be suppressed, and it is possible to manufacture an article with a high joining force between members and suppression of performance degradation due to burrs.

[0020] Hereinafter, each configuration of the adhesive sheet of the present invention will be described.

[0021] (1) Adhesive layer The adhesive layer in the present invention contains a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and a filler (D), and the content of the filler (D) is within a predetermined range.

[0022] The adhesive layer in the present invention contains a photocurable resin (A) and a thermoplastic resin (B), and these resins each have a polymerizable functional group other than a polymerizable unsaturated double bond. When the adhesive layer is irradiated with light, the polymerizable functional groups possessed by the photocurable resin (A) and the thermoplastic resin (B) are activated, and the curing proceeds in a state where the reactivity is enhanced. Therefore, the above adhesive layer suppresses the rapid curing reaction after light irradiation and can cause the curing reaction to proceed gradually. Also, since the curing reaction after light irradiation proceeds gradually, it can have flexibility even after light irradiation, enabling the joining of members. That is, the adhesive layer in the present invention is a delayed-curing type adhesive layer. Further, the adhesive layer in the present invention can have appropriate flexibility even after curing.

[0023] The adhesive layer in the present invention is a layer composed of an adhesive composition containing a photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, a thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, a photopolymerization initiator (C), and a catcher (D). That is, the total amount of the adhesive layer means the total amount of the adhesive composition constituting the adhesive layer, and the content in the adhesive layer means the content in the total amount of the adhesive composition constituting the adhesive layer. Note that the total amount of the adhesive composition does not include a solvent.

[0024] <Photocurable resin (A)> The photocurable resin (A) has a polymerizable functional group other than a polymerizable unsaturated double bond. By including the photocurable resin (A) in the adhesive layer in the present invention, polymerization occurs due to the polymerizable functional group possessed by the above photocurable resin (A) upon light irradiation, and further polymerization proceeds even during the dark reaction or at low temperatures, enabling the joining of members without being restricted by the light transmittance or heat resistance of the members.

[0025] Examples of the photocurable resin (A) include photopolymerizable compounds such as radical photopolymerizable compounds, cationic photopolymerizable compounds, and anionic photopolymerizable compounds. Among them, cationic photopolymerizable compounds and / or anionic photopolymerizable compounds are preferred. In other words, it is preferable that the photocurable resin (A) has a cationic photopolymerizable functional group and / or an anionic photopolymerizable functional group as a polymerizable functional group other than the polymerizable unsaturated double bond. By including a polymerizable compound having these functional groups in the adhesive layer, it becomes less susceptible to oxygen inhibition during curing, and a continuous reaction is likely to proceed even after light irradiation. Therefore, the members can be joined without being restricted by the light transmittance and heat resistance of the members. In particular, a cationic photopolymerizable compound is more preferable because it has excellent reactivity after light irradiation and is likely to obtain high joint strength after curing. The above-mentioned photopolymerizable compounds may be used alone or in combination.

[0026] The above-mentioned cationic photopolymerizable compound only needs to have one or more cationic photopolymerizable functional groups in one molecule, and is not particularly limited. The cationic photopolymerizable compound preferably has one or more cationic photopolymerizable functional groups such as epoxy groups, oxetanyl groups, hydroxyl groups, vinyl ether groups, episulfide groups, ethyleneimine groups, and oxazoline groups in one molecule. Among them, in order to obtain high curability and joint strength after curing, the cationic photopolymerizable compound more preferably has an epoxy group or an oxetanyl group.

[0027] As the photo cationic polymerizable compound having the epoxy group, a compound having one or more epoxy groups in one molecule can be used. Specifically, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, polyhydroxynaphthalene type epoxy resin, isocyanate-modified epoxy resin, 10-(2,5-dihydroxyphenyl)-9,10-dihydro 9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, hexanediol type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol co-condensed novolac type epoxy resin, naphthol-cresol co-condensed novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, biphenyl-modified novolac type epoxy resin, trimethylolpropane type epoxy resin, alicyclic epoxy resin, acrylic resin having an epoxy group, polyurethane resin having an epoxy group, polyester resin having an epoxy group, flexible epoxy resin, etc. can be used.

[0028] Among them, it is preferable to use at least one of an alicyclic epoxy resin and a polyfunctional aliphatic type epoxy resin, and it is more preferable to use an alicyclic epoxy resin. Since these are excellent in photo cationic polymerizability, an adhesive sheet excellent in curability can be obtained, and a suitable elastic modulus for suppressing the deformation of the adhesive layer over time after bonding can be imparted.

[0029] The epoxy resin may be a modified product. This is because by blending or adding other resin components or the like to the epoxy resin, the flexibility of the adhesive layer can be increased, and the adhesive strength and bending strength can be improved. As such modified products, CTBN (carboxyl group-terminated butadiene-acrylonitrile rubber) modified epoxy resin; epoxy resin in which various rubbers such as acrylic rubber, NBR, SBR, butyl rubber, or isoprene rubber are dispersed in the resin; epoxy resin modified with a liquid rubber as described above; epoxy resin added with various resins such as acrylic, urethane, urea, polyester, and styrene; chelate modified epoxy resin; polyol modified epoxy resin, etc. can be used.

[0030] On the other hand, examples of the oxetanyl group-containing photo cationic polymerizable compound include oxetane compounds such as 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 3-methyl-3-glycidyloxetane, 3-ethyl-3-glycidyloxetane, 3-methyl-3-hydroxymethyloxetane, 3-ethyl-3-hydroxymethyloxetane, and di{1-ethyl(3-oxetanyl)}methyl ether.

[0031] Also, as the photocurable resin (A), it is preferable to use a photocurable resin (a1) in which the temperature (Tg-Tanδ) at which the loss tangent after curing shows a maximum value is 100°C or higher. This is because high heat resistance can be imparted to the cured adhesive sheet. Among them, for the photocurable resin (a1), the temperature at which the loss tangent after curing shows a maximum value is preferably 105°C or higher, 110°C or higher, 115°C or higher, and the above temperature is preferably 250°C or lower, particularly preferably 230°C or lower, 200°C or lower. The temperature (Tg-Tanδ) at which the loss tangent after curing of the photocurable resin (a1) shows a maximum value is the value measured at a frequency of 1.0 Hz using a dynamic viscoelasticity measuring device (manufactured by Rheometric Scientific, trade name: RSA-II) for the cured product obtained by curing the photocurable resin (a1) alone.

[0032] As the photocurable resin (a1) in which the temperature (Tg-Tanδ) at which the loss tangent after curing shows a maximum value is 100°C or higher, for example, an epoxy resin that is solid at room temperature (hereinafter referred to as a room-temperature solid epoxy resin) can be mentioned. Note that room temperature means 25°C.

[0033] Specific examples of the room-temperature solid epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, polyhydroxynaphthalene type epoxy resin, isocyanate-modified epoxy resin, 10-(2,5-dihydroxyphenyl)-9,10-dihydro 9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, hexanediol type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol-phenol co-condensed novolac type epoxy resin, naphthol-cresol co-condensed novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resin, biphenyl-modified novolac type epoxy resin, and the like.

[0034] Also, when the photocurable resin (A) is an epoxy resin, it is preferable to use a combination of a solid epoxy resin at room temperature and a liquid epoxy resin at room temperature (hereinafter referred to as a room temperature liquid epoxy resin). That is, the photocurable resin (A) contained in the adhesive layer in the present invention is preferably one or more solid epoxy resins at room temperature and one or more liquid epoxy resins at room temperature. By using a combination of a solid epoxy resin at room temperature and a liquid epoxy resin at room temperature, it is easy to process into a sheet shape, and an appropriate adhesiveness can be imparted to the sheet before curing, making it easy to bond to the adherend. In addition, by using a combination of a solid epoxy resin at room temperature and a liquid epoxy resin at room temperature, it is possible to obtain excellent adhesion reliability after curing. Furthermore, by using a polyfunctional epoxy resin such as a novolac type epoxy resin as the solid epoxy resin at room temperature in combination with a liquid epoxy resin at room temperature, it is possible to obtain excellent adhesiveness even at high temperatures.

[0035] Specific examples of the room temperature liquid epoxy resin include trimethylolpropane type epoxy resins, alicyclic epoxy resins, acrylic resins having an epoxy group, polyurethane resins having an epoxy group, polyester resins having an epoxy group, and the like. Among them, alicyclic epoxy resins are preferred for the reasons described above.

[0036] The proportion of the photocurable resin (a1) in the photocurable resin (A) where the temperature (Tg-Tanδ) at which the loss tangent after curing shows a maximum value is 100 °C or higher is preferably in the range of 20% by mass to 80% by mass, more preferably in the range of 30% by mass to 70% by mass, still more preferably in the range of 35% by mass to 65% by mass, and even more preferably in the range of 40% by mass to 65% by mass. Further, when the photocurable resin (A) is an epoxy resin, the proportion of the room-temperature solid epoxy resin in the total amount of the epoxy resin is preferably in the range of 20% by mass to 80% by mass, more preferably in the range of 30% by mass to 70% by mass, still more preferably in the range of 35% by mass to 65% by mass, and even more preferably in the range of 40% by mass to 65% by mass. This is because while heat resistance of the cured sheet can be imparted, the curing time can be completed in a relatively short time. The proportion of the room-temperature solid epoxy resin in the total amount of the epoxy resin can be calculated by the following formula. <Formula> Proportion of room-temperature solid epoxy resin in total amount of epoxy resin = {Content of room-temperature solid epoxy resin [parts by mass] / (Total content of epoxy resin [parts by mass])} × 100 [mass%]

[0037] The above photocurable resin (A) preferably has a weight-average molecular weight in the range of 100 to 5000, more preferably in the range of 150 to 3000, and still more preferably in the range of 200 to 2500. By setting the weight-average molecular weight of the photocurable resin (A) within the above range, the shape of the sheet before curing becomes more stable, the handleability is improved, and the follow-up adhesion to the adherend surface can be enhanced. If the weight-average molecular weight of the photocurable resin (A) is too small, the cohesion of the adhesive layer before curing is insufficient, and problems such as bleeding of the adhesive layer over time may occur, leading to a decrease in handleability. On the other hand, if the weight-average molecular weight of the photocurable resin (A) is too large, the compatibility with the thermoplastic resin (B) may decrease, making the reaction difficult to proceed.

[0038] The measurement of the weight-average molecular weight described in this specification is a value measured under the following conditions by gel permeation chromatography (GPC) in terms of polystyrene conversion. (Conditions) · Resin sample solution; 0.4 mass% tetrahydrofuran (THF) solution · Measuring device model number; HLC-8220GPC (manufactured by Tosoh Corporation) · Column; TSKgel (manufactured by Tosoh Corporation) · Eluent; tetrahydrofuran (THF)

[0039] The content of the photocurable resin (A) in the adhesive layer in the present invention is preferably 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more in the total amount of the adhesive layer, in other words, in the total amount of the adhesive composition, and preferably 90% by mass or less or less than 90% by mass, 85% by mass or less, 80% by mass or less, 75% by mass or less, 65% by mass or less. Specifically, it is preferably 10% by mass or more and 90% by mass or less or less than 90% by mass, preferably within the range of 15% by mass to 85% by mass, preferably within the range of 20% by mass to 80% by mass, preferably within the range of 25% by mass to 75% by mass, preferably within the range of 25% by mass to 65% by mass. By setting the content of the photocurable resin (A) in the adhesive layer in the present invention within the above range, the follow-up adhesion to the step of the adherend surface is further enhanced, and two members can be firmly joined through the cured adhesive layer. When the content of the photocurable resin (A) is excessive compared to the above range, it may not be possible to process it into a sheet form. On the other hand, when it is less than the above range, the heat resistance of the cured adhesive layer may deteriorate.

[0040] <Thermoplastic resin (B)> The thermoplastic resin (B) has a polymerizable functional group other than a polymerizable unsaturated double bond. By including the above thermoplastic resin (B) in the adhesive layer in the present invention, it can react with the photocurable resin (A) mutually, suppress the rapid curing reaction after light irradiation, and make it possible to gradually progress the curing reaction. Thereby, the adhesive layer in the present invention can have flexibility even after light irradiation, can follow and adhere to the adherend surface of the member after light irradiation, and also has appropriate flexibility after curing, so that two members can be firmly joined through the adhesive layer.

[0041] The polymerizable functional group other than the polymerizable unsaturated double bond that the above thermoplastic resin (B) has is preferably a group selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group. By using the thermoplastic resin (B) having at least one polymerizable functional group selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group, it becomes possible to react with the photocurable resin (A), and suppress the rapid curing reaction after light irradiation, and it becomes possible to gradually progress the curing reaction. As a result, the adhesive layer in the present invention can have flexibility even after light irradiation, the follow-up adhesion to the step of the adherend surface is further enhanced, and two members can be firmly joined through the adhesive layer.

[0042] Examples of the above thermoplastic resin (B) include polyester resins, polyurethane resins, acrylic resins, polyvinyl acetal resins, epoxy resins (thermoplastic epoxy resins), etc. having a polymerizable functional group other than the polymerizable unsaturated double bond. These thermoplastic resins may be homopolymers or copolymers. Further, these thermoplastic resins may be used alone or in combination of two or more.

[0043] The polyurethane resin having a polymerizable functional group other than the polymerizable unsaturated double bond is preferably a polyurethane resin (B') having at least one selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group.

[0044] The polyurethane resin (B') can be obtained, for example, by reacting a polyol (b'1) and a polyisocyanate (b'2).

[0045] The polyol (b'1) preferably has a number average molecular weight in the range of 500 to 5000, and more preferably has a number average molecular weight in the range of 1000 to 3000 in order to obtain an adhesive layer excellent in shape retention, coating workability, initial cohesion, etc. The above number average molecular weight is a value measured under the following conditions.

[0046] The number average molecular weight described in this specification is a value measured under the following conditions by gel permeation chromatography (GPC) in terms of polystyrene conversion. (Conditions) · Resin sample solution: 0.4 mass% tetrahydrofuran (THF) solution · Measuring device model number: HLC-8220GPC (manufactured by Tosoh Corporation) · Column: TSKgel (manufactured by Tosoh Corporation) · Eluent: Tetrahydrofuran (THF)

[0047] As such a polyol (b'1), for example, one or more selected from the group consisting of polyester polyol, polycarbonate polyol, and polyether polyol can be preferably used.

[0048] Among them, in the present invention, as the polyol (b'1), it is preferable to use at least one or two or more of polyester polyol and polycarbonate polyol, and it is more preferable to use at least one or two or more of polyester polyol. A more preferable example is that as the polyol (b'1), it is preferable to use two or more kinds of polyester polyol. Another preferable example is that as the polyol (b'1), it is preferable to use one or two or more kinds of polyester polyol and one or two or more kinds of polycarbonate polyol. Also, in another preferable example, as the polyol (b'1), it is preferable to use one or two or more kinds of polyester polyol and one or two or more kinds of polyether polyol. By using different kinds of polyester polyols in combination, or by using a polyester polyol and other polyols in combination, the adhesive sheet of the present invention has a more stable sheet shape before curing, improved handleability, and improved follow-up adhesion to the steps of the adherend surface.

[0049] The proportion of the total amount of the polyol selected from polyester polyol, polycarbonate polyol, and polyether polyol in the above polyol (b'1) is preferably 20% by mass or more, more preferably 50% by mass or more, and particularly preferably 100% by mass in the total amount of the above polyol (b'1). This is because the adhesive layer containing the polyurethane resin (B') can maintain an adhesiveness level that allows it to be attached at room temperature, and the follow-up adhesion to the adherend surface can be further improved.

[0050] When the above polycarbonate polyol and the above polyester polyol are used in combination, the mass ratio of the polycarbonate polyol to the polyester polyol (polycarbonate polyol / polyester polyol) is preferably in the range of 0.4 to 7.0, and more preferably in the range of 1.0 to 2.0. This is because a polyurethane resin with loss tangent (tanδ40 and tanδ60) values within the desired range can be obtained, the handleability before curing is excellent, and an adhesive layer with higher follow-up adhesion to the adherend surface can be formed. Also, when the above polyether polyol and the above polyester polyol are used in combination, the mass ratio of the polyether polyol to the polyester polyol (polyether polyol / polyester polyol) can be set in the same range as above.

[0051] Examples of the above polyester polyol include those obtained by esterifying a low molecular weight polyol and a polycarboxylic acid, polyesters obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, and copolymer polyesters thereof.

[0052] Examples of the low molecular weight polyol include aliphatic alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, 1,3-butanediol, etc., and cyclohexanedimethanol, etc., which generally have a molecular weight of about 50 to 300.

[0053] Examples of the polycarboxylic acid that can be used in the production of the above polyester polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, etc., aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc., and their anhydrides or esterified products, etc.

[0054] As the above polyester polyol, it is preferable to use an aliphatic polyester polyol, and more preferably a linear aliphatic polyester polyol. This is because a polyurethane resin (B') having loss tangent (tanδ40 and tanδ60) values within a desired range can be obtained, the handleability before curing is excellent, and an adhesive layer having higher follow-up adhesion to the adherend surface can be formed. The above linear aliphatic polyester polyol refers to a polyester polyol having no alkyl group in the side chain.

[0055] Examples of the above aliphatic polyester polyol include those obtained by reacting the above aliphatic alkylene glycol with an aliphatic dicarboxylic acid, and it is preferable to use an aliphatic polyester polyol obtained by an esterification reaction of 1,6-hexanediol and adipic acid.

[0056] Furthermore, it is preferable to use an aromatic polyester polyol as the above-mentioned polyester polyol. This is because the elastic modulus of the polyurethane resin (B') can be increased to improve rigidity, and it becomes possible to suppress joint displacement, warping, and deformation over time before and after curing of the adhesive layer. Examples of the aromatic polyester polyol include those obtained by reacting an aromatic polyol with an aliphatic or aromatic dicarboxylic acid. Among them, an aromatic polyester polyol obtained by reacting an ethylene oxide adduct of bisphenol A with phthalic acid and adipic acid is preferably used.

[0057] As the above-mentioned polyester polyol, only an aliphatic polyester polyol may be used, only an aromatic polyester polyol may be used, or an aliphatic polyester polyol and an aromatic polyester polyol may be used in combination. Among them, it is preferable that the above-mentioned polyester polyol is used in combination with an aliphatic polyester polyol and an aromatic polyester polyol, that is, the above-mentioned polyester polyol uses one or more aromatic polyester polyols and one or more aliphatic polyester polyols. The adhesive layer containing the polyurethane resin (B') prepared by the combined use of the aromatic polyester polyol and the aliphatic polyester polyol can achieve a balance between the hardness and softness of the layer before and after curing, exhibit high follow-up adhesion to the step of the adherend surface, and suppress joint displacement, warping, and deformation of the adhesive layer over time. In order to balance the above-mentioned opposite physical properties well, the content ratio (aromatic polyester polyol / aliphatic polyester polyol) of the aromatic polyester polyol and the aliphatic polyester polyol is preferably in the range of 20 / 80 to 90 / 10 by mass ratio, and more preferably in the range of 50 / 50 to 80 / 20.

[0058] The above polyester polyol preferably has a number average molecular weight in the range of 1000 to 5000. This is because a polyurethane resin (B') with values of loss tangent (tanδ40 and tanδ60) within a desired range can be obtained, it has excellent handleability before curing, and an adhesive layer with higher follow-up adhesion to the adherend surface can be formed.

[0059] In particular, when using a polyester polyol obtained by reacting an aliphatic diol such as 1,2-ethanediol or 1,4-butanediol with adipic acid as the above polyester polyol, it is preferable to use one having a number average molecular weight in the range of 1100 to 2900. When using a polyester polyol obtained by reacting 1,6-hexanediol with adipic acid, it is preferable to use one having a number average molecular weight in the range of 1100 to 5000. When using a polyester polyol obtained by reacting 1,6-hexanediol with sebacic acid, it is preferable to use one having a number average molecular weight in the range of 1000 to 5000.

[0060] When the above polyol (b'1) contains a polyester polyol and a polyol other than the above polyester polyol, the above polyester polyol can be used in the range of 10% to 80% by mass based on the total amount of the above polyol (b'1). Among them, it is preferably used in the range of 20% to 80% by mass, more preferably in the range of 30% to 70% by mass, and even more preferably in the range of 40% to 50% by mass. This is because the adhesive layer containing the polyurethane resin (B') can maintain an adhesive property level that can be adhered at room temperature, and the follow-up adhesion to the step of the adherend surface can be further improved.

[0061] As the polycarbonate polyol, for example, those obtained by reacting a carbonic acid ester and / or phosgene with a low molecular weight polyol can be used. As the carbonic acid ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclo carbonate, diphenyl carbonate, etc. can be used.

[0062] As the low molecular weight polyol that can react with the above carbonic acid ester or phosgene, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2 - propanediol, 1,3 - propanediol, dipropylene glycol, tripropylene glycol, 1,2 - butanediol, 1,3 - butanediol, 1,4 - butanediol, 2,3 - butanediol, 1,5 - pentanediol, 1,5 - hexanediol, 1,6 - hexanediol, 2,5 - hexanediol, 1,7 - heptanediol, 1,8 - octanediol, 1,9 - nonanediol, 1,10 - decanediol, 1,11 - undecanediol, 1,12 - dodecanediol, 2 - methyl - 1,3 - propanediol, neopentyl glycol, 2 - butyl - 2 - ethyl - 1,3 - propanediol, 3 - methyl - 1,5 - pentanediol, 2 - ethyl - 1,3 - hexanediol, 2 - methyl - 1,8 - octanediol, 1,4 - cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4’ - biphenol, etc. can be used.

[0063] Also, as the polycarbonate polyol, it is preferable to use an aliphatic polycarbonate polyol or an alicyclic polycarbonate polyol.

[0064] As the aliphatic polycarbonate polyol, it is preferable to use one obtained by reacting a dialkyl carbonate with one or more polyols selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol. This is because the adhesive layer containing the polyurethane resin (B') can have an adhesiveness level that allows for sticking at room temperature.

[0065] As the alicyclic polycarbonate polyol, it is preferable to use one obtained by reacting a dialkyl carbonate with a polyol containing one or more selected from the group consisting of cyclohexanedimethanol and its derivatives. This is because the adhesive layer containing the polyurethane resin (B') can have an adhesiveness level that allows for sticking at room temperature and excellent initial cohesion.

[0066] The above polycarbonate polyol preferably has a number average molecular weight in the range of 500 to 5000, and more preferably has a number average molecular weight in the range of 800 to 3000. This is because a polyurethane resin (B') with loss tangent (tanδ40 and tanδ60) values within a desired range can be obtained, the handleability before curing is excellent, and an adhesive layer with higher follow-up adhesion to the adherend surface can be obtained.

[0067] When the above polyol (b'1) contains the above polycarbonate polyol and a polyol other than the above polycarbonate polyol, the above polycarbonate polyol is preferably used in the range of 20% to 80% by mass, more preferably in the range of 30% to 70% by mass, and preferably in the range of 40% to 50% by mass based on the total amount of the above polyol (b'1). This is because the adhesive layer containing the polyurethane resin (B') can maintain an adhesiveness level that allows for sticking at room temperature and light, and the follow-up adhesion to the adherend surface can be further improved.

[0068] Examples of the polyether polyol include those obtained by addition polymerization of an alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0069] Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3 - butanediol, 1,4 - butanediol, 1,6 - hexanediol, bisphenol A, glycerin, trimethylolethane, trimethylolpropane, etc., which can be used.

[0070] Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, etc., which can be used.

[0071] As the polyether polyol, it is preferable to use an aliphatic polyether polyol or a polyether polyol having an alicyclic structure.

[0072] Examples of the polyether polyol include polytetramethylene glycol obtained by ring - opening polymerization of tetrahydrofuran, a polytetramethylene glycol derivative obtained by reacting tetrahydrofuran with an alkyl - substituted tetrahydrofuran, a polytetramethylene glycol derivative obtained by copolymerizing neopentyl glycol and tetrahydrofuran, etc. Among them, as the polyether polyol, in order to maintain the adhesiveness at a level possible at room temperature for the adhesive sheet containing the adhesive layer and to improve excellent flexibility, durability (especially hydrolysis resistance), etc., it is preferable to use polytetramethylene glycol (PTMG) and polytetramethylene glycol derivative (PTXG).

[0073] In addition to the above, other polyols can be used as the polyol (b'1). Examples of the other polyols include acrylic polyols.

[0074] As the polyisocyanate (b'2), an alicyclic polyisocyanate, an aliphatic polyisocyanate, an aromatic polyisocyanate, etc. can be used, and it is preferable to use an alicyclic polyisocyanate.

[0075] Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4- and / or 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, and 2,5- and / or 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane triisocyanate, etc., which can be used alone or in combination of two or more.

[0076] Among the above-mentioned alicyclic polyisocyanates, in order to obtain an adhesive sheet having good reactivity with the above polyol (b'1) and excellent heat resistance, light transmittance, etc., it is preferable to use 4,4'-dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (BICH).

[0077] As a method for producing a polyurethane resin (B') having an isocyanate group by reacting the above polyol (b'1) with the above polyisocyanate (b'2), for example, a method in which the above polyol (b'1) charged into a reaction vessel is heated under normal pressure or reduced pressure conditions to remove moisture, and then the above polyisocyanate (b'2) is supplied all at once or in portions and reacted can be mentioned.

[0078] The reaction between the above polyol (b’1) and the above polyisocyanate (b’2) is preferably carried out in a range where the equivalent ratio of the isocyanate groups in the above polyisocyanate (b’2) to the hydroxyl groups in the above polyol (b’1) (hereinafter referred to as [NCO / OH equivalent ratio]) is in the range of 1.1 to 20.0, more preferably in the range of 1.1 to 13.0, even more preferably in the range of 1.1 to 5.0, and particularly preferably in the range of 1.5 to 3.0.

[0079] The reaction conditions (temperature, time, etc.) for the above polyol (b’1) and the above polyisocyanate (b’2) may be appropriately set in consideration of various conditions such as safety, quality, and cost, and are not particularly limited. For example, the reaction temperature is preferably in the range of 70 to 120°C, and the reaction time is preferably in the range of 30 minutes to 5 hours.

[0080] When reacting the above polyol (b’1) and the above polyisocyanate (b’2), if necessary, a catalyst such as a tertiary amine catalyst or an organometallic catalyst can be used.

[0081] Also, the above reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. Examples of the above organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone, ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate, aromatic hydrocarbon solvents such as toluene and xylene, and amide solvents such as dimethylformamide and dimethylacetamide, which can be used alone or in combination of two or more. The above organic solvent may be removed by an appropriate method such as heating under reduced pressure or drying at normal pressure during the production of the above polyurethane resin (B’) or after the production of the above polyurethane resin (B’).

[0082] As the polyurethane resin (B') having an isocyanate group, for example, a polyurethane resin (B'1) having an isocyanate group obtained by reacting a polyol (b'1) and a polyisocyanate (b'2) can be used. Details (types, formulations, etc.) of the polyol (b'1) and the polyisocyanate (b'2) used in the preparation of the polyurethane resin (B') having an isocyanate group can be the same as the details of the polyol (b'1) and the polyisocyanate (b'2) described above.

[0083] As the polyurethane resin (B') having a hydroxyl group, for example, a polyurethane resin (B'2) having a hydroxyl group obtained by reacting a polyol (b'1) and a polyisocyanate (b'2) can be used.

[0084] Details (types, formulations, etc.) of the polyol (b'1) and the polyisocyanate (b'2) used in the preparation of the polyurethane resin (B') having a hydroxyl group can be the same as the details of the polyol (b'1) and the polyisocyanate (b'2) used in the synthesis of the polyurethane resin (B') having an isocyanate group.

[0085] As the polyurethane resin (B') having an oxetanyl group or an epoxy group, for example 1) A polyurethane (B'1) having an isocyanate group, and 2) A monomer (B") having a functional group (b"1) capable of reacting with an isocyanate group, an oxetanyl group or an epoxy group, and a polymerizable functional group (b"2) other than one or more polymerizable unsaturated double bonds, and The polyurethane resin (B'3) obtained by reacting can be used.

[0086] As the functional group (b"1) capable of reacting with the isocyanate group, for example, a hydroxyl group, an amino group, a carboxyl group, a mercapto group, etc. can be used, and among them, it is preferable to use a hydroxyl group and an amino group.

[0087] The polymerizable functional group (b”2) other than the above-mentioned polymerizable unsaturated double bond refers to something other than a functional group having so-called radical polymerizability, such as a functional group having cationic polymerizability, a functional group having anionic polymerizability, etc. Examples include an epoxy group, an oxetanyl group, an ethylene sulfide group, etc.

[0088] The above monomer (B”) is not particularly limited as long as it has the functional group (b”1) and the polymerizable functional group (b”2). Examples include 3-ethyl-3-(4-hydroxybutyl)oxymethyl-oxetane, 3-hydroxymethyl-3-ethyloxetane, 2-hydroxymethyloxetane, 3-hydroxyoxetane, etc.

[0089] The above monomer (B”) is preferably used in the range of 5 parts by mass to 20 parts by mass, more preferably in the range of 5 parts by mass to 15 parts by mass, based on 100 parts by mass of the polyurethane resin (B’1).

[0090] More specifically, as the above monomer (B”), an amount capable of supplying a functional group capable of reacting with the above isocyanate group is preferably more than 50 mol% and 100 mol% or less, more preferably 60 mol% to 100 mol%, still more preferably 80 mol% to 100 mol%, based on the number of moles of the isocyanate group possessed by the polyurethane resin (B’1). Thereby, a polyurethane resin excellent in appropriate flexibility, rapid curability, shape retention, mechanical strength, durability (especially hydrolysis resistance), and follow-up adhesion to the adherend surface can be obtained.

[0091] When reacting the urethane resin (B’1) with the monomer (B”), a urethanization catalyst can be used as needed. The urethanization catalyst can be appropriately added at any stage of the urethanization reaction. The urethanization reaction is preferably carried out until the isocyanate group content (%) becomes substantially constant. Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine, and N-methylmorpholine; organic metal salts such as potassium acetate, zinc stearate, and stannous octylate; and organic metal compounds such as dibutyltin dilaurate.

[0092] In addition, epoxy resins having polymerizable functional groups other than polymerizable unsaturated double bonds include polymers or copolymers of epoxy compounds having a linear structure, and copolymers of an epoxy compound and a monomer copolymerizable with the epoxy compound having a linear structure. Specifically, bisphenol A type epoxy resin, bisphenol fluorene type epoxy resin, cresol novolak type epoxy resin, phenol novolak type epoxy resin, cycloaliphatic type epoxy resin, long-chain aliphatic type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, etc. can be mentioned, and bisphenol A type epoxy resin and bisphenol fluorene type epoxy resin are preferred.

[0093] Among them, the adhesive layer in the present invention preferably contains, as the thermoplastic resin (B), one or more resins selected from the group consisting of a polyurethane resin, an acrylic resin, and an epoxy resin having a polymerizable functional group other than a polymerizable unsaturated double bond, and preferably contains at least one or more polyurethane resins having a polymerizable functional group other than a polymerizable unsaturated double bond. By using a polyurethane resin having a polymerizable functional group other than a polymerizable unsaturated double bond as the thermoplastic resin (B), it is possible to suppress a rapid curing reaction after light irradiation and gradually progress the curing reaction, so that it can have the flexibility required for bonding even after light irradiation. As a result, the adhesive layer in the present invention can closely adhere to the adherend surface of the member after light irradiation, and also has appropriate flexibility after curing, so that the members can be firmly joined via the adhesive layer.

[0094] The melting point of the above thermoplastic resin (B) is preferably in the range of 30°C to 120°C, more preferably in the range of 35°C to 100°C, and still more preferably in the range of 40°C to 80°C. By using the thermoplastic resin (B) having a melting point within the above range, the sheet shape of the adhesive sheet of the present invention is more stable before curing, the handleability is improved, and the follow-up adhesion to the adherend surface can be improved.

[0095] The melting point of the thermoplastic resin (B) refers to the temperature indicating the maximum exothermic peak (exothermic peak top) observed when the temperature is raised from 20°C to 150°C at a heating rate of 10°C / min under heating conditions, held for 1 minute, then once cooled to -10°C under cooling conditions of 10°C / min, held for 10 minutes, and then measured again under heating conditions of 10°C / min using a differential scanning calorimetry (DSC method).

[0096] The above-mentioned thermoplastic resin (B) preferably has a weight average molecular weight in the range of 5,500 to 2,000,000, more preferably in the range of 5,500 to 1,000,000, and even more preferably in the range of 5,500 to 800,000. By setting the weight average molecular weight of the thermoplastic resin (B) within the above range, the sheet shape before curing becomes more stable, the handleability is improved, and the follow-up adhesion to the adherend surface can be enhanced. If the weight average molecular weight of the thermoplastic resin (B) is too small, the cohesive force of the adhesive layer before curing may be insufficient, and bleeding of the adhesive layer may occur over time, making the handleability likely to deteriorate. On the other hand, if the weight average molecular weight of the thermoplastic resin (B) is too large, the compatibility with the photocurable resin (A) may decrease, making the reaction difficult to proceed.

[0097] In the present invention, the content of the thermoplastic resin (B) in the adhesive layer is preferably 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more in the total amount of the adhesive layer, in other words, in the total amount of the adhesive composition, and is preferably 80% by mass or less, 70% by mass or less, 60% by mass or less, 50% by mass or less. Specifically, it is preferably in the range of 5% by mass to 80% by mass, more preferably in the range of 10% by mass to 60% by mass, and even more preferably in the range of 20% by mass to 50% by mass. By setting the content of the thermoplastic resin (B) in the adhesive layer within the above range, it is possible to have flexibility that can ensure followability to the adherend even after light irradiation, and while having appropriate flexibility even after curing, the elongation of the adhesive layer in the dicing process can be suppressed. If the content of the thermoplastic resin (B) is excessive compared to the above range, the heat resistance of the cured product may deteriorate. On the other hand, if it is less than the above range, the proportion of the high molecular weight component in the entire adhesive layer may decrease, and it may not be possible to process it into a sheet shape.

[0098] The content ratio of the above-mentioned thermoplastic resin (B) to the content of the photocurable resin (A) ([content of thermoplastic resin (B) / content of photocurable resin (A)]) is preferably in the range of 0.1 to 10 on a mass basis, preferably in the range of 0.15 to 2, preferably in the range of 0.2 to 1.7, preferably in the range of 0.3 to 1.5, preferably in the range of 0.5 to 1.4, and preferably in the range of 0.5 to 1.0. By setting the content ratio of the thermoplastic resin (B) to the content of the photocurable resin (A) within the above range, flexibility can be imparted to ensure followability to the adherend even after light irradiation, and the adhesive layer can be made difficult to stretch in the dicing process after curing. Further, by making the ratio of the thermoplastic resin (B) lower than that of the photocurable resin (A), excellent adhesion reliability after curing can be obtained, and excellent adhesiveness at high temperatures can be obtained.

[0099] <Photoinitiator (C)> The adhesive layer in the present invention contains one or more photoinitiators (C), so that the reactivity after irradiation with active energy rays is promoted and the bonding property after curing can be enhanced. Further, since the adhesive layer contains a photoinitiator (C) that is activated by light and the reaction proceeds, the reaction continues as it is even after the irradiation with active energy rays is stopped. Therefore, the reaction proceeds even in a dark place or at a low temperature, and a good curing reaction can be obtained. Thereby, high bonding property can be obtained without damaging the members to be joined, deforming the members due to strain between the members, or causing cracks between the adhesive sheet and the members.

[0100] The above-mentioned photoinitiator (C) is not particularly limited as long as it is activated by light. Examples of the above-mentioned photoinitiator (C) include photo radical polymerization initiators, photo cationic polymerization initiators, and photo anionic polymerization initiators. Among them, at least one of the photo cationic polymerization initiator and the photo anionic polymerization initiator is preferable, and the photo cationic polymerization initiator is more preferable because the polymerization by dark reaction can be suitably adjusted.

[0101] The above-mentioned photo cationic polymerization initiator is not particularly limited as long as it can induce a ring-opening reaction of a cationic polymerizable functional group by light of the wavelength to be used. Among them, a compound that induces a ring-opening reaction of a cationic polymerizable functional group by light with a wavelength of 300 nm to 370 nm and is inactive in the wavelength region exceeding 370 nm is preferably used. Examples of such photo cationic polymerization initiators include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts.

[0102] Specific examples of onium salts include, for example, Optomer SP-150, Optomer SP-170, Optomer SP-171 (all manufactured by ADEKA), UVE-1014 (manufactured by General Electronics), OMNICAT250, OMNICAT270 (all manufactured by IGM Resin), IRGACURE290 (manufactured by BASF), Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L (all manufactured by Sinsin Chemical Industry Co., Ltd.), CPI-100P, CPI-101A, CPI-200K (all manufactured by San-Apro), etc.

[0103] The photo cationic polymerization initiator may be used alone or in combination of two or more. Furthermore, a plurality of photo cationic polymerization initiators having different effective active wavelengths may be used for two-stage curing.

[0104] The above-mentioned photo cationic polymerization initiator may be used in combination with a sensitizer such as anthracene-based or thioxanthone-based as necessary.

[0105] The above-mentioned photo cationic polymerization initiator is preferably contained in the range of 0.001% by mass to 30% by mass, more preferably in the range of 0.01% by mass to 20% by mass, and still more preferably in the range of 0.1% by mass to 10% by mass with respect to the total amount of the adhesive layer, in other words, the adhesive composition forming the adhesive layer. If the blending ratio of the above-mentioned photo cationic polymerization initiator is too small, the curing necessary for the expression of high bondability becomes insufficient. If it is too large, the curability is improved, but the progress of the curing reaction after light irradiation becomes fast, and it becomes difficult to sufficiently follow and adhere to the adherend surface and firmly bond the members together.

[0106] <Filler (D)> The adhesive layer in the present invention contains Filler (D) within a predetermined content range. In the present invention, the content of Filler (D) in the adhesive layer may be 5% by mass or more and 45% by mass or less, preferably 6% by mass or more and 43% by mass or less, more preferably 7% by mass or more and 40% by mass or less, still more preferably 8% by mass or more and 39% by mass or less, and particularly preferably 10% by mass or more and 35% by mass or less. By setting the content of Filler (D) in the total amount of the adhesive layer (total amount of the adhesive composition) within the above range, the adhesive sheet can adhere to the adherend without being inhibited by Filler (D), and on the other hand, the generation of burrs during dicing can be suppressed. Note that if the content of Filler (D) is too high, the adhesion to the adherend may become poor, and if it is too low, burrs may be generated during dicing.

[0107] Also, the volume ratio of Filler (D) in the adhesive layer is preferably 2% by volume or more and 30% by volume or less, more preferably 3% by volume or more and 27% by volume or less, still more preferably 3.5% by volume or more and 25% by volume or less, and particularly preferably 4% by volume or more and 22% by volume or less. By setting the volume ratio of Filler (D) in the adhesive layer within the above range, the adhesive sheet can adhere to the adherend without being inhibited by Filler (D), and on the other hand, the generation of burrs during dicing can be suppressed. Note that if the volume ratio of Filler (D) in the adhesive layer is too large, the adhesion to the adherend may become poor, and if it is too small, burrs may be generated during dicing.

[0108] The volume ratio of Filler (D) in the adhesive layer is calculated by dividing the volume amount of Filler (D) by the volume of the adhesive layer, where the volume amount of Filler (D) is calculated from the value obtained by dividing the contained weight of Filler (D) in the adhesive layer by the specific gravity of Filler (D).

[0109] Filler (D) can be used alone or in combination of two or more.

[0110] The filler (D) may be an inorganic filler or an organic filler. Further, the adhesive layer in the present invention may contain one or more inorganic fillers or organic fillers, or may contain one or more inorganic fillers and one or more organic fillers.

[0111] Examples of the inorganic filler include fillers composed of inorganic materials such as metals, metal compounds, alloys, inorganic salts, carbon materials, and clay minerals. Specific examples of the inorganic materials include metals such as aluminum, gold, silver, copper, and nickel and their alloys; inorganic salts such as calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydrogen carbonate, magnesium hydrogen carbonate, zinc carbonate, calcium phosphate, magnesium phosphate, sodium phosphate, potassium phosphate, barium phosphate, sodium citrate, potassium citrate, calcium citrate, magnesium citrate, magnesium oxalate, sodium oxalate, potassium oxalate, sodium tartrate, potassium tartrate, calcium silicate, magnesium silicate, calcium oxide, and magnesium oxide; metal sulfides such as zinc sulfide; metal nitrides such as titanium nitride, aluminum nitride, silicon nitride, and boron nitride; viscosity minerals such as talc and mica; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; metal oxides such as aluminum oxide and titanium oxide; aluminum borate whiskers, crystalline silica, amorphous silica, amorphous carbon, graphite, and glass.

[0112] It is preferable that the inorganic filler exhibits basicity. When the inorganic filler exhibits basicity, particularly when the adherend surface of the member to be bonded includes a metal surface, the inorganic filler can capture the acid generated in the adhesive layer and the metal ions generated on the adherend surface, thereby suppressing the corrosion of the metal surface.

[0113] Examples of the inorganic filler exhibiting basicity include inorganic salts and metal compounds having basic groups introduced on the surface. The metal compound having basic groups introduced on the surface can be obtained by subjecting the surface of the metal compound to basic treatment. The basic treatment refers to a treatment for making the surface of the metal compound basic by reacting or adsorbing a silane coupling agent having a basic group or a nitrogen compound such as hexamethyldisilazane to the metal compound. The basic treatment is not limited to this as long as it can make the surface of the metal compound basic. Examples of the basic group include an organic amino group, a hydroxyl group, and the like.

[0114] Examples of the organic filler include fillers composed of resin materials. Specific examples of the resin material include polymethyl methacrylate (PMMA), polyimide, polyamideimide, polyetheretherketone, polyetherimide, and polyesterimide.

[0115] The filler (D) can have various shapes such as particulate, acicular, and flaky. Among them, the particulate shape is preferable from the viewpoint of uniform dispersibility and the like. When the filler (D) is particulate, the average particle diameter of the filler (D) is preferably 0.5 μm or more and 100 μm or less, more preferably 1 μm or more and 100 μm or less, still more preferably 2 μm or more and 90 μm or less, and particularly preferably 3 μm or more and 50 μm or less. By using a filler having an average particle diameter within the above range, the end face of the adhesive layer does not elongate during dicing and can be suitably cut, and it is possible to hardly generate burrs. When the average particle diameter of the filler (D) is larger than the above range, it may be difficult to process it into a sheet shape, and when it is smaller than the above range, the adhesive layer may elongate during dicing.

[0116] When the filler (D) is a primary particle without aggregation, the average particle diameter of the primary particle is preferably within the above range. On the other hand, when the filler (D) aggregates to form secondary particles, the size of the secondary particles is preferably within the above range.

[0117] The average particle diameter of the filler (D) shall be the value measured by scanning electron microscope observation (SEM). Specifically, the average particle diameter was measured using a surface observation device (VE-9800 manufactured by Keyence Corporation).

[0118] Among them, the adhesive layer in the present invention preferably contains an inorganic filler as the filler (D), more preferably contains at least one or two or more fillers composed of inorganic materials selected from inorganic salts and metal compounds, and still more preferably contains at least one of calcium carbonate particles and silica particles.

[0119] The filler (D) is preferably dispersed in the adhesive layer. This is because if the filler (D) is unevenly distributed, burrs cannot be sufficiently suppressed throughout the adhesive layer during dicing. Here, the filler (D) being dispersed in the adhesive layer means that when any location after sheet processing is cut into 5 cm × 5 cm and observed under a microscope, there are less than 3 aggregates of the filler (D) exceeding 1000 μm.

[0120] The filler (D) may be buried in the adhesive layer, or a part of the surface may be exposed from the adhesive layer.

[0121] <Other components (E)> In addition to the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D), the adhesive layer can contain other components (E) as necessary.

[0122] The adhesive layer in the present invention may contain a pressure-sensitive adhesive resin. This is because the adhesive sheet of the present invention can exhibit good room-temperature bonding properties, and the follow-up adhesion to the adherend surface can be further improved.

[0123] The above pressure-sensitive adhesive resin preferably has a weight average molecular weight in the range of 2000 to 2000000, more preferably in the range of 5000 to 1000000, and still more preferably in the range of 5000 to 800000.

[0124] Examples of the above-mentioned pressure-sensitive adhesive resin include polyester resin, polyurethane resin, poly(meth)acrylate resin, polyvinyl acetal resin, etc. These pressure-sensitive adhesive resins may be homopolymers or copolymers. Further, these pressure-sensitive adhesive resins may be used alone or in combination of two or more.

[0125] The above-mentioned pressure-sensitive adhesive resin preferably has a glass transition temperature in the range of -30°C to 20°C, more preferably in the range of -25°C to 10°C. By including a pressure-sensitive adhesive resin having a glass transition temperature within the above range in the adhesive layer, the adhesive sheet of the present invention can exhibit good adhesiveness and a high elastic modulus at normal temperature, and can exhibit good conformability and high bonding strength to the adherend.

[0126] The glass transition temperature can be calculated, for example, using a dynamic viscoelasticity tester (manufactured by Rheometric Scientific, product name: ARES 2KSTD). A test piece of the pressure-sensitive adhesive resin is sandwiched between parallel disks, which are the measurement part of the tester, and the storage elastic modulus (G') and loss elastic modulus (G") at a frequency of 1 Hz are measured. It can be calculated as the temperature at which the loss tangent (tanδ), which is the value obtained by dividing the above loss elastic modulus (G") by the above storage elastic modulus (G'), reaches the maximum value.

[0127] The above-mentioned pressure-sensitive adhesive resin may have a functional group that can react with a crosslinking agent or the functional groups contained in the above-mentioned photocurable resin (A) or thermoplastic resin (B). This is because the above-mentioned pressure-sensitive adhesive resin can be crosslinked. Examples of the above-mentioned functional group include a hydroxyl group, a carboxyl group, an epoxy group, an amino group, etc. It is preferable to select appropriately in a range that does not inhibit the polymerization reaction of the photocurable resin (A) and the thermoplastic resin (B).

[0128] The above-mentioned pressure-sensitive adhesive resin is preferably contained in the range of 0.1 part by mass to 100 parts by mass, more preferably in the range of 1 part by mass to 50 parts by mass, and still more preferably in the range of 5 parts by mass to 30 parts by mass, in the total amount of the adhesive layer, in other words, in the total amount of the adhesive composition forming the adhesive layer. By setting the blending ratio of the above-mentioned pressure-sensitive adhesive resin within the above range, an adhesive sheet excellent in adhesion at room temperature can be obtained without reducing the bonding property after curing of the adhesive layer.

[0129] The adhesive layer in the present invention can contain, as other components, a silane coupling agent, a phosphate-based additive, an acrylate-based additive, etc. When the material of the adherend surface contains glass, the above-mentioned adhesive layer can contain a silane coupling agent rich in reactivity with glass, thereby further enhancing the adhesiveness to the adherend. Further, the above-mentioned adhesive layer may contain a photocurable silane coupling agent capable of reacting with a photocurable resin (A), a thermoplastic resin (B), etc.

[0130] In addition, the adhesive layer in the present invention can contain, as other components, for example, a softening agent, a stabilizer, an adhesion promoter, a leveling agent, an antifoaming agent, a plasticizer, a tackifier resin, fibers, an antioxidant, a hydrolysis inhibitor, a thickener, a coloring agent such as a pigment, a filler, an optional component such as a tackifier resin, etc.

[0131] <Others> The adhesive layer in the present invention contains one or more resins (AA) having an epoxy group or an oxetanyl group and having a weight average molecular weight in the range of 100 to 5,000, and a polymerizable functional group other than a polymerizable unsaturated double bond, and having a weight average molecular weight in the range of 5,500 to 2,000,000, and is selected from the group consisting of a polyester resin, a polyurethane resin, an acrylic resin, a polyvinyl acetal resin, and an epoxy resin (thermoplastic epoxy resin) (BB). It contains one or more types of resins, a photopolymerization initiator (C), and a filler (D), and the content of the filler (D) in the adhesive layer is preferably 5% by mass or more and 45% by mass or less. By adopting the above composition containing two or more types of resins combined with a resin having a low weight average molecular weight and a resin having a high weight average molecular weight, the effects of the present invention can be achieved. Here, the resin (AA) and the resin (BB) correspond to the above-described photocurable resin (A) and thermoplastic resin (B), respectively.

[0132] <Physical properties of the adhesive layer> The adhesive layer in the present invention preferably has a thickness of 10 μm or more and 3,000 μm or less, more preferably 20 μm or more and 2,500 μm or less, still more preferably 30 μm or more and 2,000 μm or less, and most preferably 50 μm or more and 650 μm or less. By setting the thickness of the adhesive layer within the above range, it has excellent handleability before curing, and can exhibit high follow-up adhesion to the adherend surface and a metal corrosion inhibition effect. If the thickness of the adhesive layer is smaller than the above range, it may not be possible to contain a desired amount of the filler (D), and defects during dicing processing such as the generation of burrs and peeling off from the adherend surface may not be sufficiently suppressed, or sufficient adhesive strength may not be obtained due to the thin thickness. On the other hand, if the thickness of the adhesive layer is larger than the above range, it is difficult to process it into a sheet shape. As described later, when the adhesive layer in the present invention is a multilayer body formed by laminating a plurality of adhesive layers, the thickness of the adhesive layer refers to the total thickness of the multilayer body.

[0133] The adhesive layer in the present invention preferably has a loss tangent (tanδ) of less than 1.5, more preferably from 0.01 to 1.0, and still more preferably from 0.1 to 0.8 at a frequency of 1.0 Hz and a temperature of 23°C before curing. This is because the thickness of the adhesive sheet can be kept constant, the handleability before curing is excellent, and the follow-up adhesion to the adherend surface is further improved before and after curing.

[0134] For the loss tangent (tanδ) of the adhesive layer, a test piece obtained by cutting the adhesive layer into a circular shape with a thickness of 1 mm and a diameter of 8 mm is prepared. Using a dynamic viscoelasticity tester (manufactured by Rheometric Scientific, trade name: ARES 2KSTD), the prepared test piece is sandwiched between the parallel disks which are the measuring part of the tester, and the storage modulus (G') and loss modulus (G") at a frequency of 1.0 Hz and a temperature of 23°C are measured. The loss tangent (tanδ) is the value (G" / G') obtained by dividing the above loss modulus (G") by the above storage modulus (G').

[0135] The loss tangent (tanδ) of the adhesive layer can be adjusted by appropriately selecting the composition such as the photocurable resin (A), thermoplastic resin (B), and other components as necessary, and its average molecular weight, etc.

[0136] The adhesive layer in the present invention preferably has a melting point of 25°C or higher, more preferably 30°C or higher, still more preferably 35°C or higher, and most preferably 40°C or higher. Also, the above melting point is preferably 120°C or lower, more preferably 90°C or lower, and still more preferably 60°C or lower. More specifically, the melting point of the adhesive layer is preferably in the range of 30°C to 120°C, more preferably in the range of 30°C to 90°C, and most preferably in the range of 40°C to 85°C. By setting the melting point of the adhesive layer within the above range, the adhesive sheet of the present invention has excellent handleability before curing and further improved follow-up adhesion to the adherend surface. Note that the melting point of the adhesive layer is synonymous with the melting point of the adhesive composition constituting the adhesive layer.

[0137] The melting point of the adhesive layer is the temperature indicated by the maximum exothermic peak (the top of the exothermic peak) observed when the temperature is raised from 20°C to 150°C at a rate of 10°C / min under the temperature-raising condition, held for 1 minute, then once cooled to -10°C under the temperature-lowering condition of 10°C / min, held for 10 minutes, and then measured again under the temperature-raising condition of 10°C / min using differential scanning calorimetry (DSC method).

[0138] In the present invention, the storage elastic modulus (E’) of the cured adhesive layer at a frequency of 1 Hz and a temperature of 25°C 25 is preferably 1.0×10 5 Pa or more, more preferably 1.0×10 6 Pa or more, and even more preferably 1.0×10 7 Pa or more. This is because by the cured adhesive layer showing a desired storage elastic modulus under predetermined conditions, it is possible to suppress displacement and deformation of the adhesive layer over time after bonding.

[0139] Also, in the present invention, the storage elastic modulus (E’40) of the cured adhesive layer at a frequency of 1 Hz and a temperature of 40°C is preferably 1.0×10 4 Pa or more, and the storage elastic modulus (E’60) at a frequency of 1 Hz and a temperature of 60°C is preferably 1.0×10 4 Pa or more. This is because by the cured adhesive layer showing a desired storage elastic modulus under predetermined conditions, it becomes possible to firmly bond the members together.

[0140] The storage elastic modulus at each temperature of the cured adhesive layer is a value measured using a dynamic viscoelasticity measuring device (manufactured by Rheometric Scientific, trade name: RSA-II) with a test piece formed by punching out a 100-μm-thick cured adhesive layer into the shape of test piece type 5 of JIS K 7127 using a dumbbell cutter.

[0141] The adhesive sheet of the present invention preferably has a tensile elongation at break of 0.5% or more, more preferably 1.0% or more, 1.5% or more, 2.0% or more, 3.0% or more when the cured adhesive sheet is pulled at a pulling speed of 300 mm / min at 25°C. Further, the above-mentioned tensile elongation at break is preferably 30% or less, more preferably 25% or less, 20% or less, 15% or less, 10% or less. Specifically, the above-mentioned tensile elongation at break can be 1.0% or more and 25% or less, 1.5% or more and 20% or less, 2.0% or more and 15% or less, 3.0% or more and 10% or less. When the tensile elongation at break of the cured adhesive sheet is within the above range, the sheet does not stretch excessively during dicing and burrs are less likely to occur.

[0142] The tensile elongation at break of the cured adhesive sheet can be measured by a method conforming to JIS K7127-1999 [Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets]. The test piece used for the measurement is obtained by cutting the adhesive sheet into a size of 10 mm in width and 150 mm in length, with the length between the gauge lines being 50 mm (conforming to test piece type 2 of JIS K7127-1999), and after irradiating ultraviolet rays with an intensity of 300 mW / cm 2 for 15 seconds using an air-cooled mercury lamp (manufactured by Eye Graphics Co., Ltd.), heating and leaving it at 80°C for 3 hours, and leaving it in a 23°C environment for 30 minutes or more and then cooling it to cure the adhesive layer.

[0143] In the adhesive sheet of the present invention, the gel fraction of the cured adhesive layer is preferably 40% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and particularly preferably 70% by mass or more and 100% by mass or less. By setting the gel fraction within the above range, it is possible to firmly bond the members even after curing and to impart heat resistance.

[0144] The gel fraction is a value calculated based on the following formula from the mass of the adhesive layer remaining in the above solvent after immersing the adhesive layer of the cured adhesive sheet of the present invention in toluene adjusted to 23°C for 24 hours and the mass of the adhesive layer before toluene immersion. Gel fraction (mass %) = {(mass of the adhesive layer of the adhesive sheet remaining undissolved in toluene) / (mass of the adhesive layer of the adhesive sheet before toluene immersion)} × 100

[0145] (2) Aspect of the adhesive sheet The adhesive sheet of the present invention may be in an aspect having an adhesive layer containing the above-described composition, and may have any configuration as necessary.

[0146] One aspect (Aspect (I)) of the adhesive sheet of the present invention includes an aspect composed only of an adhesive layer, that is, a substrate-free aspect. The adhesive sheet of Aspect (I) can be an aspect having only a single-layer adhesive layer composed of an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D). Further, the adhesive sheet of Aspect (I) has only an adhesive layer of a multilayer body in which two or more layers are laminated, and at least the outermost layers on both sides of the adhesive layer of the multilayer body may be composed of an adhesive composition containing the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D). Among them, it is preferable that all of the plurality of layers constituting the adhesive layer of the multilayer body are composed of an adhesive composition containing the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D).

[0147] In the adhesive sheet of Aspect (I), release liners may be disposed on one main surface or both main surfaces of the pair of opposing main surfaces of the adhesive layer. The adhesive sheet of Aspect (I) is used by peeling off the release liner when bonding to a member. Therefore, in a laminate in which a pair of members are joined via the adhesive sheet of Aspect (I), the release liner is not included in the configuration of the adhesive sheet.

[0148] As another aspect (Aspect (II)) of the adhesive sheet of the present invention, there are provided a base material, a first adhesive layer formed on the first main surface of the base material, and a second adhesive layer formed on the second main surface of the base material facing the first main surface of the base material. The first adhesive layer and the second adhesive layer are each composed of an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D). The adhesive sheet of Aspect (II) can increase the strength as a sheet by having a base material between the two adhesive layers. In Aspect (II), only one of the first adhesive layer and the second adhesive layer may be composed of an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D).

[0149] In the adhesive sheet of Aspect (II), the base material is not particularly limited. For example, a plastic film made of a polyester resin or a polyolefin resin, or a plastic foam made of a polyolefin resin, a polyurethane resin, a polychloroprene resin, an acrylic resin, or the like can be used. The base material preferably has light transmissivity. By irradiating light from one adhesive layer side, the other adhesive layer can also be activated through the base material to cause a polymerization reaction.

[0150] In the adhesive sheet of Aspect (II), a release liner may be disposed on at least one of the surface of the first adhesive layer opposite to the surface in contact with the base material and the surface of the second adhesive layer opposite to the surface in contact with the base material, or release liners may be disposed on both surfaces. The adhesive sheet of Aspect (II) is used by peeling off the release liner when bonding to a member. Therefore, in a laminate in which a pair of members are joined via the adhesive sheet of Aspect (II), the release liner is not included in the configuration of the adhesive sheet.

[0151] As the release liner, for example, paper such as kraft paper, glassine paper, and high-quality paper; resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate; laminated paper obtained by laminating the above paper and resin film; and those obtained by applying a blocking treatment to one or both sides of the above paper with clay, polyvinyl alcohol, etc., and then applying a release treatment with a silicone-based resin or the like can be used.

[0152] The thickness of the adhesive sheet of the present invention is preferably one having a thickness of 10 μm to 3000 μm, more preferably 20 μm or more and 2500 μm or less, still more preferably 30 μm or more and 2000 μm or less, and most preferably 50 μm or more and 650 μm or less.

[0153] When the adhesive sheet of the present invention is irradiated with light, polymerization starts in the adhesive layer and curing proceeds. In the present invention, the adhesive layer is activated by light, so that curing does not proceed regardless of the storage temperature in the state where light is not irradiated, and the storage stability before curing is good. Further, in the adhesive layer of the present invention, since the reactive sites are activated by light irradiation without heating, the curing reaction can proceed even at low temperatures.

[0154] The adhesive sheet of the present invention can accelerate the curing reaction by further applying external stimuli such as heat and moisture (humidity) in addition to light. Among them, it is preferable to use light and heat in combination as the curing means of the adhesive sheet of the present invention. By irradiating the adhesive sheet with light first, the adhesive layer is activated to start polymerization, and after the adhesive sheet is bonded to a member (adherend), heating can accelerate the curing reaction. Thereby, curing by high-temperature heating is not required as in the case of a thermosetting adhesive sheet, and the curing reaction can proceed even at low temperatures. When heat is used in combination, since the progress of the reaction has already started by light irradiation, heat is used only for the purpose of accelerating the curing reaction, and it is not necessary to heat at a high temperature, and a good curing reaction can be obtained even with a reaction at a low temperature for a short time.

[0155] (3) Method for manufacturing an adhesive sheet The adhesive sheet of the present invention can be produced using an adhesive solution obtained by mixing an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D) in a solvent. Specifically, the adhesive sheet of the present invention can be produced, for example, by applying the above-described adhesive solution to the surface of a release sheet, drying to form an adhesive layer, and removing the release sheet. By forming an adhesive layer using an adhesive solution in which the adhesive composition is mixed with a solvent, the dispersibility of the additive (D) in the adhesive layer is improved as compared with the case of directly applying the adhesive.

[0156] Further, the adhesive sheet of the present invention can be produced, for example, by applying the above-described adhesive solution to both sides of a substrate, drying to form an adhesive layer.

[0157] Further, the adhesive sheet of the present invention can be produced, for example, by applying the above-described adhesive solution to the surface of a release sheet, drying to form an adhesive layer, and attaching a substrate to the surface of the adhesive layer.

[0158] When producing an adhesive sheet in which two or more adhesive layers having the same or different compositions are laminated, for example, an adhesive solution containing the adhesive composition 1 is applied to both sides of a substrate, dried to form a first adhesive layer 1, and an adhesive solution containing the adhesive composition 2 is applied to the surface of the first adhesive layer 1 and dried to form a second adhesive layer 2. In this case, at least the adhesive composition 2 contains the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D). Among them, it is preferable that both the adhesive compositions 1 and 2 contain the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D).

[0159] In addition, the adhesive sheet of the present invention can be manufactured, for example, by applying an adhesive solution containing the adhesive composition 1 to the surface of a release sheet, drying to form the adhesive layer 1, applying an adhesive solution containing another adhesive composition 2 to the surface of the adhesive layer 1, and drying to form the adhesive layer 2. In this case, at least one of the adhesive compositions 1 and 2 contains at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D). Among them, it is preferable that both the adhesive compositions 1 and 2 contain at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D).

[0160] The adhesive solution used in the method for manufacturing the adhesive sheet of the present invention can be prepared by mixing an adhesive composition containing at least the above-described photocurable resin (A), thermoplastic resin (B), photopolymerization initiator (C), and filler (D) with a solvent. Examples of the solvent used in the adhesive solution include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; and aromatic hydrocarbon solvents such as toluene and xylene. For mixing the adhesive composition and the solvent, a dissolver, a butterfly mixer, a BDM two-axis mixer, a planetary mixer, etc. can be used.

[0161] In the method for manufacturing the adhesive sheet of the present invention, after applying the adhesive solution, a drying step for removing the solvent is included. The drying step is preferably carried out at a temperature of preferably 40°C to 120°C, more preferably about 50°C to 90°C. This is because it can suppress the progress of the curing reaction of the adhesive sheet before light irradiation and can also suppress the foaming of the sheet surface due to the rapid volatilization of the solvent and the like.

[0162] (4) Use The adhesive sheet of the present invention can be used without being limited by the light transmissibility of the member. Therefore, the member joined using the adhesive sheet of the present invention may or may not have light transmissibility. In particular, the adhesive sheet of the present invention can be suitably used for joining a member with low light transmissibility or an opaque member. As described above, the adhesive sheet of the present invention has a slow curing reaction rate after light irradiation and can have flexibility even after light irradiation. For this reason, when joining members, by irradiating the adhesive sheet with light in advance, the curing reaction proceeds without irradiating the adhesive sheet with light through the members, and the members can be firmly joined. Here, it is preferable that the member (adherend) has a light transmittance of 90% or less in the wavelength range of 200 nm to 780 nm. In particular, a transmittance of 80% or less, 70% or less, 60% or less, or 50% or less is preferable. In addition, an opaque member refers to a member having a light transmittance of 0% in the above wavelength range. The light transmittance of the adherend (member) is a value measured with an ultraviolet-visible spectrophotometer such as V-570 manufactured by JASCO Corporation.

[0163] Further, the adhesive sheet of the present invention can be used without being limited by the heat resistance of the member. Therefore, the member joined using the adhesive sheet of the present invention may or may not have heat resistance. As described above, since the curing reaction of the adhesive sheet of the present invention proceeds by light irradiation and it has flexibility even after light irradiation, the curing reaction proceeds without heating or pressurizing at a high temperature. In addition, in order to accelerate the curing reaction, light irradiation and heat treatment may be used in combination as curing means, and it is preferable that the above member has heat resistance that can withstand the heating temperature of the heat treatment performed to accelerate the curing reaction after light irradiation.

[0164] The adhesive sheet of the present invention is suitably used for dicing processing applications. In other words, the adhesive sheet of the present invention is suitable for the production of a laminate to be diced, specifically, for the production of a laminate in which members are arranged on one or both sides of the adhesive sheet and the members are fixed by dicing, or for the production of a laminate in which a plurality of members are attached to at least one surface of the adhesive sheet. Examples of the laminate with members attached to multiple sides include a laminate with components used in an image display device or a semiconductor wafer attached to multiple sides.

[0165] Examples of the image display device include mobile terminals (PDAs) such as personal computers, mobile phones, smartphones, tablet PCs, game machines, televisions (TVs), car navigation systems, touch panels, pen tablets, etc., image display devices using an image display panel equipped with LCD, PDP or EL, organic EL, micro LED, quantum dot (QD), etc., and large image display devices used for industrial and advertising purposes. Examples of the components used in the image display device include an image display panel, a circuit board, a rear cover, a bezel, a frame, a chassis, a semiconductor chip, and a panel reinforcing member composed of aluminum or carbon fiber resin.

[0166] 2. Laminate The laminate of the present invention has the adhesive sheet described in the section of "1. Adhesive Sheet" above, a first member bonded to the first main surface of the adhesive sheet, and a second member bonded to the second main surface of the adhesive sheet.

[0167] In the laminate of the present invention, the adhesive layer of the adhesive sheet is cured. That is, in the laminate of the present invention, the first member and the second member are joined by the cured adhesive layer of the adhesive sheet. In other words, the first member and the second member are joined by the cured product layer of the adhesive composition described in the section of "1. Adhesive Sheet" above.

[0168] According to the laminate of the present invention, since the first and second members are joined via the adhesive sheet described in the section of "1. Adhesive Sheet" above, the members are difficult to peel off and can exhibit a high interlayer peeling force. In addition, the generation of burrs, interfacial peeling, etc. can be suppressed by dicing.

[0169] In the laminate of the present invention, it is sufficient that the first member is bonded to the first main surface of the adhesive sheet described in the section of "1. Adhesive Sheet" above, and the second member is bonded to the second main surface of the adhesive sheet facing the first main surface. The number of the first and second members is not limited. That is, in the laminate of the present invention, one first member may be bonded to the first main surface of the adhesive sheet, and one second member may be joined to the second main surface of the adhesive sheet. One first member may be bonded to the first main surface of the adhesive sheet, and a plurality of second members may be provided on the second main surface of the adhesive sheet. A plurality of first members may be bonded to the first main surface of the adhesive sheet, and a plurality of second members may be provided on the second main surface of the adhesive sheet.

[0170] Among them, in the laminate of the present invention, it is preferable that at least one of the first member and the second member is bonded to the adhesive sheet in a plurality. This is because a laminate with the members attached to multiple surfaces can be obtained, and the effect of using the above-described adhesive sheet during dicing to separate into individual pieces is more effectively exerted.

[0171] The members in the laminate of the present invention may or may not have light transmissivity. The light transmittance of the member with low light transmissivity is as described in the section of "1. Adhesive Sheet" above. In addition, the above member may or may not have heat resistance, but it preferably has heat resistance that can withstand the heating temperature of the heat treatment performed to promote the curing reaction after light irradiation.

[0172] Further, in the laminate of the present invention, when the adhesive layer contains an inorganic filler exhibiting basicity, at least one of the first member and the second member includes a metal surface on the adherend surface, so that in addition to suppressing the generation of burrs, interfacial peeling, etc. by dicing, it is possible to suppress the corrosion of the metal surface.

[0173] The member having a metal surface on the adherend surface is not particularly limited, and examples thereof include a substrate and a wiring substrate having metal wiring on one surface of the substrate. Particularly in the case of a wiring substrate having a patterned metal wiring, where the surface has uneven steps due to the wiring pattern and other members, in the laminate of the present invention, the adhesive sheet can follow and closely adhere to such surface steps, so that the wiring substrate and other members can be firmly joined, and also, since corrosion of the metal wiring hardly occurs, a decrease in the function as a wiring substrate can be suppressed for a long period.

[0174] The laminate of the present invention is preferably used in an image display device, and particularly preferably used in the manufacture of a constituent member of an image display device. Examples of the image display device include mobile terminals (PDAs) such as personal computers, mobile phones, smartphones, tablet PCs, game machines, televisions (TVs), car navigation systems, touch panels, pen tablets, etc., and image display devices using an image display panel equipped with LCD, PDP or EL, organic EL, micro LED, quantum dot (QD), etc. Examples of the constituent members of the image display device include an image display panel, a circuit board, a rear cover, a bezel, a frame, a chassis, a semiconductor chip, etc.

[0175] 3. Method for manufacturing a laminate The method for manufacturing a laminate of the present invention is a method for manufacturing a laminate using the adhesive sheet described in the section of "1. Adhesive sheet" above, and includes a step [1] of bonding a first member to the first main surface of the adhesive sheet, a step [2] of bonding a second member to the second main surface of the adhesive sheet, and a step [3] of curing the adhesive layer of the adhesive sheet, and further includes a step of irradiating an active energy ray to the first main surface or the second main surface of the adhesive sheet before the step [1] or between the step [1] and the step [2] (hereinafter, may be referred to as step [0]).

[0176] In the present invention, if the adhesive sheet is the adhesive sheet of the above-described aspect (I), the first and second main surfaces of the adhesive sheet refer to two outermost surfaces facing each other of the single-layer or multi-layer adhesive layer. Further, if the adhesive sheet in the present invention is the adhesive sheet of the above-described aspect (II), the first and second main surfaces of the adhesive sheet refer to the surface on the first adhesive layer side and the surface on the second adhesive layer side of the adhesive sheet of aspect (II), respectively.

[0177] In the above step [1], it is preferable to press-bond and bond the first member to the first main surface of the adhesive sheet. Further, in the above step [2], it is preferable to press-bond and bond the second member to the second main surface of the adhesive sheet. By press-bonding and bonding the member to the adhesive sheet, the adhesive sheet can easily follow the adherend surface of the member, and the adhesion between the adhesive sheet and the member can be enhanced. Therefore, the bonding strength between the first member and the second member through the cured adhesive layer is further increased.

[0178] In the above steps [1] and [2], the pressure when press-bonding the member to the adhesive sheet can be within the range of 0.1 to 3000 KPa, preferably within the range of 0.5 to 1000 kPa, and more preferably within the range of 1.0 to 500 kPa. By press-bonding within the above range, the member can be bonded to the adhesive sheet without being damaged, and the adhesion required to obtain a high bonding strength can be obtained.

[0179] In the above steps [1] and [2], the member may be pressure-bonded to the adhesive sheet while heating. By pressure-bonding while heating, when joining the members through the above adhesive sheet, they can adhere more firmly and a high bonding strength can be obtained. The heating temperature can be set within a range that does not cause damage to the member, deformation of the member due to strain occurring between the members, or cracking between the bonding material and the member. Preferably, it can be 150°C or lower, 120°C or lower, 100°C or lower, 80°C or lower, 70°C or lower. By setting the upper limit of the heating temperature, damage to the member can be suppressed, and deformation of the member due to strain occurring between the members and cracking between the adhesive sheet and the member can be suppressed. Also, the heating temperature can preferably be 5°C or higher, 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher. This is because by setting the lower limit of the heating temperature, the followability of the adhesive sheet to the adherend surface is improved. The pressure-bonding time is not particularly limited as long as it is a time that allows sufficient follow-up adhesion to the adherend surface of the member.

[0180] The above step [3] may involve a heat treatment. In the manufacturing method of the present invention, since the curing reaction of the adhesive sheet starts by irradiating active energy rays, curing proceeds even at room temperature. However, by performing the above step [3] while heating, when joining the members through the above adhesive sheet, the curing reaction can be promoted and a high bonding strength can be obtained in a shorter time.

[0181] When performing a heat treatment in the above step [3], the heating conditions can be set within a range that does not cause damage to the members to be laminated, deformation of the members due to strain occurring between the members, or cracking between the adhesive sheet and the members. The heating temperature is preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, and most preferably 80°C or lower in order to suppress damage to the members to be laminated and deformation and flow of the bonding material.

[0182] In the above step [3], it is preferable to advance the curing reaction so that the cured adhesive layer exhibits the gel fraction described in the section of "1. Adhesive Sheet" above.

[0183] The step of irradiating the active energy rays onto the first major surface or the second major surface of the sheet (step [0]) can be carried out before the above step [1]. In this case, it is preferable that steps [1] and [2] are carried out within 24 hours after carrying out step [0], more preferably within 12 hours, still more preferably within 3 hours, and most preferably within 1 hour, because when the adhesive sheet is attached to the member, it adheres more firmly and a high bonding strength can be obtained.

[0184] Also, the above step [0] may be carried out between the above steps [1] and [2]. In this case, it is preferable that step [2] is carried out within 24 hours after carrying out step [0], more preferably within 12 hours, still more preferably within 3 hours, and most preferably within 1 hour, because when the adhesive sheet is attached to the member, it adheres more firmly and a high bonding strength can be obtained.

[0185] As the active energy rays, ultraviolet rays, visible light, etc. are preferably used, and among them, it is preferable to use ultraviolet rays. The above ultraviolet rays may be irradiated in an inert gas atmosphere such as nitrogen gas or in an air atmosphere in order to efficiently carry out the curing reaction by ultraviolet rays. Further, if necessary, heat may be used in combination as an energy source, and after irradiating light, heating may be carried out.

[0186] Also, the light to be irradiated preferably has a wavelength region capable of activating the photopolymerization initiator, and among them, it is preferable to use active energy rays having a wavelength of 300 nm or more and 420 nm or less.

[0187] Examples of the light source for irradiating active energy rays include, for example, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, electrodeless lamps (fusion lamps), chemical lamps, black light lamps, xenon lamps, mercury-xenon lamps, short arc lamps, helium-cadmium lasers, argon lasers, sunlight, LEDs, germicidal lamps, carbon arcs, scanning type, curtain type electron beam accelerators, etc. Further, a xenon-flash lamp capable of irradiating light in a flash is preferable because it can minimize the influence of heat.

[0188] The irradiation intensity of the above active energy rays is preferably 0.1 to 1000 mW / cm 2 is more preferably 0.5 to 800 mW, and even more preferably 0.1 to 400 mW / cm 2 is even more preferable. Also, the irradiation time of the above active energy rays is preferably 1 to 60 seconds, more preferably 5 to 50 seconds, and even more preferably 10 to 40 seconds. By setting the irradiation intensity and time within the above ranges, the heat generated when irradiating the active energy rays can be reduced, so that the curing rate after irradiating the active energy rays can be suitably adjusted.

[0189] The above irradiation of the active energy rays may be performed once or may be divided into a plurality of times for irradiation.

[0190] Specific examples of the laminate that can be manufactured according to the present invention include the specific examples described in the above section "2. Laminate".

[0191] 4. Method for manufacturing an article The method for manufacturing an article of the present invention is a method for manufacturing an article using the adhesive sheet described in the section of "1. Adhesive Sheet" above, and includes a step [1] of bonding a first member to the first main surface of the adhesive sheet, a step [2] of bonding a second member to the second main surface of the adhesive sheet, a step [3] of curing the adhesive layer of the adhesive sheet to form a laminate, and a step [4] of cutting the laminate into a plurality of articles. Further, before the step [1], or between the step [1] and the step [2], there is a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays.

[0192] According to the method for manufacturing an article of the present invention, since the adhesive sheet described in the section of "1. Adhesive Sheet" above is used, generation of burrs can be suppressed in the step [4], that is, the dicing (cutting) step.

[0193] Regarding the steps [1] to [3] in the method for manufacturing an article of the present invention, since they are the same as the steps [1] to [3] described in the section of "3. Method for manufacturing a laminate" above, the description here is omitted.

[0194] In the step [4], as the method for cutting the laminate, a known method can be used, for example, blade dicing, laser dicing, plasma dicing, or braking, etc. Further, the cutting (dicing) device used in the step [4] is not particularly limited, and a conventionally known one can be used.

[0195] The article manufactured by the method for manufacturing an article of the present invention is not particularly limited, and examples include semiconductor wafer chips, image display members, etc.

[0196] The present disclosure is not limited to the above embodiments. The above embodiments are examples, and those having substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibiting the same operational effects are included in the technical scope of the present disclosure regardless of what they are.

Example

[0197] The present invention will be described more specifically below with reference to Examples and Comparative Examples.

[0198] 1. Synthesis Examples of Thermoplastic Resin (B) <Preparation of Polyurethane (B-1)> In a reaction vessel, 50.3 parts by mass of an aromatic polyester polyol having a number average molecular weight of 1300 obtained by reacting an ethylene oxide adduct of bisphenol A, phthalic acid and adipic acid, 32 parts by mass of an aliphatic polyester polyol having a number average molecular weight of 3500 obtained by reacting 1,6-hexanediol and dodecanedioic acid, 32.2 parts by mass of a polypropylene glycol having a number average molecular weight of 1000, and 1.8 parts by mass of an ethylene oxide adduct of bisphenol A were mixed and heated to 100 °C under reduced pressure conditions to dehydrate until the moisture content became 0.05% by mass, thereby obtaining a mixture (1).

[0199] Next, the cooled mixture (1) was mixed with 7.9 parts by mass of 4,4′-diphenylmethane diisocyanate, and then the temperature was raised to 100 °C and reacted for 3 hours until the hydroxyl group content became constant, thereby obtaining polyurethane (B-1). Note that the above polyurethane (B-1) has a hydroxyl group as a polymerizable functional group.

[0200] <Preparation of Polyurethane (B-2)> In a reaction vessel, 50.3 parts by mass of an aromatic polyester polyol having a number average molecular weight of 1300 obtained by reacting an ethylene oxide adduct of bisphenol A, phthalic acid and adipic acid, 32 parts by mass of an aliphatic polyester polyol having a number average molecular weight of 3500 obtained by reacting 1,6-hexanediol and dodecanedioic acid, 32.2 parts by mass of a polypropylene glycol having a number average molecular weight of 1000, and 1.8 parts by mass of an ethylene oxide adduct of bisphenol A were mixed and heated to 100 °C under reduced pressure conditions to dehydrate until the moisture content became 0.05% by mass, thereby obtaining a mixture (2).

[0201] Next, the mixture (2) cooled to 70°C was mixed with 4.3 parts by mass of 4,4'-diphenylmethane diisocyanate and 4.3 parts by mass of 2,4'-diphenylmethane diisocyanate, and then heated to 100°C and reacted for 5 hours until the hydroxyl group content became constant to obtain polyurethane (B-2). Note that the above polyurethane (B-2) has a hydroxyl group as a polymerizable functional group.

[0202] <Preparation of Polyurethane (B-3)> In a reaction vessel, 60 parts by mass of an aliphatic polycarbonate polyol having a number average molecular weight of 2000 obtained by reacting 1,5-pentanediol, 1,6-hexanediol, and dialkyl carbonate, and 20 parts by mass of a polyester polyol having a number average molecular weight of 1000 obtained by reacting 1,4-butanediol and adipic acid were mixed and heated to 100°C under reduced pressure conditions to dehydrate until the water content became 0.05% by mass to obtain a mixture (3).

[0203] Next, the mixture (3) cooled to 70°C was mixed with 20 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, and then heated to 100°C and reacted for 3 hours to obtain a urethane prepolymer having an isocyanate group. 100 parts by mass of the above urethane prepolymer heated and melted at 100°C was mixed with 11.4 parts by mass of 2-hydroxyethyl acrylate and 0.01 parts by mass of stannous octylate, and reacted at 100°C until the NCO% became constant to obtain polyurethane (B-3). Note that polyurethane (B-3) has a polymerizable unsaturated double bond as a polymerizable functional group, and the isocyanate group content (NCO%) was 0% by mass.

[0204] (Example 1) 33 parts by mass of the above polyurethane (B-1), 22 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), 45 parts by mass of a cresol novolak type epoxy resin ("N-685-EXP-S" manufactured by DIC Corporation), 1.6 parts by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%), and 40 parts by mass of calcium bicarbonate particles ("BF-200" manufactured by Shiraishi Calcium Co., Ltd., average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added and adjusted so that the non-volatile content became 75% by mass to obtain an adhesive solution containing an adhesive composition (a-1).

[0205] Next, on the surface of a release liner A (a polyethylene terephthalate film with a thickness of 50 μm, one side of which is subjected to a release treatment with a silicone compound), the adhesive solution containing the above adhesive composition (a-1) was applied using a rod-shaped metal applicator so that the thickness after drying became 150 μm, and it was put into a dryer at 85°C for 5 minutes and dried to obtain a coating layer of the adhesive composition (a-1).

[0206] Furthermore, three of the above coating layers were laminated by bonding to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (a polyethylene terephthalate film with a thickness of 38 μm, one side of which is subjected to a release treatment with a silicone compound) was bonded to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0207] (Example 2) 43 parts by mass of the above polyurethane (B-2), 22 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), 35 parts by mass of a cresol novolak type epoxy resin ("N-685-EXP-S" manufactured by DIC Corporation), 2.0 parts by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%), and 13.3 parts by mass of calcium bicarbonate particles ("BF-200" manufactured by Shiraishi Calcium Co., Ltd., average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added and adjusted so that the non-volatile content became 75% by mass to obtain an adhesive solution containing an adhesive composition (a-2).

[0208] Next, an adhesive solution containing the above adhesive composition (a-2) was applied to the surface of the release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying was 150 μm, and then it was put into a dryer at 85°C for 5 minutes to be dried, thereby obtaining a coating layer of the adhesive composition (a-2).

[0209] Furthermore, three of the above coating layers were laminated by bonding to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm was subjected to a release treatment with a silicone compound) was bonded to the other side of the adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0210] (Example 3) 43 parts by mass of the above polyurethane (B-2), 22 parts by mass of an alicyclic epoxy resin (“CEL-2021P” manufactured by Daicel Corporation), 35 parts by mass of a cresol novolak type epoxy resin (“N-685-EXP-S” manufactured by DIC Corporation), 2.0 parts by mass of a sulfonium salt-based photo cationic polymerization initiator (“CPI-100P” manufactured by San-Apro Limited, solid content concentration 50%), and 10.0 parts by mass of hydrophobic silica particles (“Silophobic 603” manufactured by Fuji Silysia Chemical Ltd., average particle diameter 6.7 μm) were mixed and stirred, and methyl ethyl ketone was added to adjust the non-volatile content to 75% by mass, thereby obtaining an adhesive solution containing an adhesive composition (a-3).

[0211] Next, an adhesive solution containing the above adhesive composition (a-3) was applied to the surface of the release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying was 150 μm, and then it was put into a dryer at 85°C for 5 minutes to be dried, thereby obtaining a coating layer of the adhesive composition (a-3).

[0212] Furthermore, three coating layers were laminated together to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm was subjected to a release treatment with a silicone compound) was laminated on the other side of the adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0213] (Example 4) 33 parts by mass of the above polyurethane (B-1), 22 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), 45 parts by mass of a cresol novolak type epoxy resin ("N-685-EXP-S" manufactured by DIC Corporation), 1.6 parts by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%), and 6 parts by mass of calcium bicarbonate particles ("BF-200" manufactured by Shiraishi Calcium Co., Ltd., average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added to adjust the non-volatile content to 75% by mass to obtain an adhesive solution containing an adhesive composition (a-4).

[0214] Next, an adhesive solution containing the above adhesive composition (a-4) was applied to the surface of the release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying was 150 μm, and it was put into a dryer at 85°C for 5 minutes and dried to obtain a coating layer of the adhesive composition (a-4).

[0215] Furthermore, three coating layers were laminated together to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm was subjected to a release treatment with a silicone compound) was laminated on the other side of the adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0216] (Example 5) 58 parts by mass of the above polyurethane (B-1), 22 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), 20 parts by mass of a cresol novolak type epoxy resin ("N-685-EXP-S" manufactured by DIC Corporation), 2.0 parts by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%), and 60 parts by mass of calcium bicarbonate particles ("BF-200" manufactured by Shiraishi Calcium Co., Ltd., average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added and adjusted so that the non-volatile content became 75% by mass to obtain an adhesive solution containing an adhesive composition (a-5).

[0217] Next, on the surface of a release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm is subjected to a release treatment with a silicone compound), the adhesive solution containing the above adhesive composition (a-5) was applied using a rod-shaped metal applicator so that the thickness after drying became 150 μm, and it was put into a dryer at 85°C for 5 minutes and dried to obtain a coating layer of the adhesive composition (a-5).

[0218] Furthermore, three of the above coating layers were laminated by bonding to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm is subjected to a release treatment with a silicone compound) was bonded to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0219] (Comparative Example 1) 43 parts by mass of the above polyurethane (B-2), 22 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), 35 parts by mass of a cresol novolak type epoxy resin ("N-685-EXP-S" manufactured by DIC Corporation), and 1.0 part by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%) were mixed and stirred, and methyl ethyl ketone was added and adjusted so that the non-volatile content became 75% by mass to obtain an adhesive solution containing an adhesive composition (b-1).

[0220] Next, an adhesive solution containing the above adhesive composition (b-1) was applied to the surface of the release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and then it was put into a dryer at 85°C for 5 minutes to be dried, thereby obtaining a coating layer of the adhesive composition (b-1).

[0221] Furthermore, three of the above coating layers were laminated by bonding to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side. A release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm was subjected to a release treatment with a silicone compound) was bonded to the other side of the above adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0222] (Comparative Example 2) 43 parts by mass of the above polyurethane (B-2), 22 parts by mass of an alicyclic epoxy resin (manufactured by Daicel Corporation, "CEL-2021P"), 35 parts by mass of a cresol novolak type epoxy resin (manufactured by DIC Corporation, "N-685-EXP-S"), 2.0 parts by mass of a sulfonium salt-based photo cationic polymerization initiator (manufactured by San-Apro, "CPI-100P", solid content concentration 50%), and 190 parts by mass of calcium bicarbonate particles (manufactured by Shiraishi Calcium Co., Ltd., "BF-200", average particle size 5 μm) were mixed and stirred, and methyl ethyl ketone was added to adjust the non-volatile content to 75% by mass, thereby obtaining an adhesive solution containing the adhesive composition (b-2).

[0223] Next, an adhesive solution containing the above adhesive composition (b-2) was applied to the surface of the release liner A (one side of a polyethylene terephthalate film with a thickness of 50 μm was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying would be 150 μm, and then it was put into a dryer at 85°C for 5 minutes to be dried, thereby forming a coating layer of the adhesive composition (b-2).

[0224] Furthermore, three coating layers were laminated together to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (a polyethylene terephthalate film with a thickness of 38 μm, one side of which was subjected to a release treatment with a silicone compound) was laminated on the other side of the adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0225] (Comparative Example 3) 100 parts by mass of the urethane resin (B-3), 43 parts by mass of an alicyclic epoxy resin ("CEL-2021P" manufactured by Daicel Corporation), and 11.4 parts by mass of a sulfonium salt-based photo cationic polymerization initiator ("CPI-100P" manufactured by San-Apro, solid content concentration 50%) were mixed and stirred, and methyl ethyl ketone was added to adjust the non-volatile content to 75% by mass to obtain an adhesive solution containing an adhesive composition (b-3).

[0226] Next, an adhesive solution containing the adhesive composition (b-3) was applied to the surface of the release liner A (a polyethylene terephthalate film with a thickness of 50 μm, one side of which was subjected to a release treatment with a silicone compound) using a rod-shaped metal applicator so that the thickness after drying was 150 μm, and it was put into a dryer at 85°C for 5 minutes to be dried to form a coating layer of the adhesive composition (b-3).

[0227] Furthermore, three coating layers were laminated together to form an adhesive layer of a multilayer body with a thickness of 450 μm having a release liner A on one side, and a release liner B (a polyethylene terephthalate film with a thickness of 38 μm, one side of which was subjected to a release treatment with a silicone compound) was laminated on the other side of the adhesive layer to obtain an adhesive sheet with a total thickness of 450 μm (excluding the thickness of the release liner).

[0228] 3. Evaluation [Initial Adhesion Strength after Lamination] The adhesive sheets obtained in the examples and comparative examples were cut into test samples with a size of 10 mm in width and 10 mm in length. One release liner of the above test sample was removed, and it was press-bonded to an aluminum plate (light-impermeable material) with a width of 15 mm, a length of 150 mm, and a thickness of 0.05 mm having a smooth surface at a pressure of 0.05 MPa for 10 seconds in a temperature environment of 23°C to obtain an adhered object. After leaving this adhered object in a temperature environment of 23°C for 60 minutes, it was irradiated with ultraviolet rays having an intensity of 300 mW / cm 2 for 15 seconds using an air-cooled mercury lamp (manufactured by Eye Graphics Co., Ltd.). At this time, the above ultraviolet irradiation was performed without removing the release liner.

[0229] After leaving the adhered object after ultraviolet irradiation in a temperature environment of 23°C for 10 minutes, the release liner was removed, and it was press-bonded at 1.0 MPa for 10 minutes using a hot press device heated to 80°C to an aluminum plate (light-impermeable material) with a width of 15 mm, a length of 150 mm, and a thickness of 0.05 mm having a smooth surface to obtain a laminate.

[0230] The laminate after press-bonding was left to heat at 80°C for 1 hour, and the one left in a 23°C environment for 30 minutes or more and cooled was used as a test sample. The ends of the aluminum plate were each chucked, and the shear adhesive strength [MPa] of the above test sample was determined by performing a tensile test at a tensile speed of 50 mm / min in the 180-degree direction using a tensile tester.

[0231] [Volume ratio of filler (D) in the adhesive sheet] The volume ratio of filler (D) in the adhesive sheet was calculated by calculating the volume amount of filler (D) from the value obtained by dividing the contained weight of filler (D) in the adhesive layer by the specific gravity of filler (D), and then dividing that value by the volume of the adhesive layer.

[0232] [Elongation at break] The adhesive sheets obtained in the examples and comparative examples were cut into pieces with a width of 10 mm and a length of 150 mm, and those with a length of 50 mm between the reference lines were used as test pieces (conforming to test piece type 2 of JIS K7127-1999). Next, the above test pieces were irradiated with ultraviolet rays of 300 mW / cm 2 using an air-cooled mercury lamp (manufactured by Eye Graphics Co., Ltd.) for 15 seconds. At this time, the above ultraviolet irradiation was performed without removing the release liner. The adhered material after the above ultraviolet irradiation was left to heat at 80 °C for 3 hours, and then left to stand in an environment of 23 °C for 30 minutes or more and cooled to obtain an evaluation sample.

[0233] The elongation at break in tension of the evaluation sample at 25 °C was measured using a tensile testing machine under the condition of a tensile speed of 300 mm / min. The measurement was carried out in accordance with the method specified in JIS K7127-1999 [Plastics - Test methods for tensile properties - Part 3: Test conditions for films and sheets].

[0234] [Proper Dicing] The adhesive sheets obtained in the examples and comparative examples were cut into pieces with a width of 80 mm and a length of 120 mm. Next, one release liner of the above cut adhesive sheet was removed, and it was press-bonded to a CFRP plate (plain weave, epoxy resin-based) with a width of 80 mm, a length of 120 mm, and a thickness of 1.5 mm at a temperature of 80 °C and a pressure of 0.05 MPa for 30 seconds to bond them together.

[0235] After leaving the above adhered material in a temperature environment of 23 °C for 60 minutes, it was irradiated with ultraviolet rays of 300 mW / cm2 using an air-cooled mercury lamp (manufactured by Eye Graphics Co., Ltd.) for 15 seconds. At this time, the above ultraviolet irradiation was performed without removing the release liner.

[0236] After leaving the adhered material after the above ultraviolet irradiation in a temperature environment of 23 °C for 10 minutes, the release liner was removed, and it was press-bonded to a blue plate glass plate with a width of 80 mm, a length of 120 mm, and a thickness of 0.5 mm at 1.0 MPa for 10 minutes using a hot press device heated to 80 °C.

[0237] The laminated body after the above press bonding was left to heat at 80°C for 1 hour, left to stand in a 23°C environment for 30 minutes or more, and then cooled to be used as a test sample. Next, it was cut into a size of 60 mm × 100 mm using a dicing saw (manufactured by DISCO, product name "DAD-522"). For the blade, ZH05-SD4000-N1-70-BB (manufactured by DISCO) was used, and the conditions were a blade height of 90 μm, a blade rotation speed of 40,000 rpm, and a dicing speed of 40 mm / second.

[0238] The cross-section of the test sample after dicing was observed using a digital microscope VHX-7000 (manufactured by KEYENCE CORPORATION). Observation was carried out at four corners after dicing, and the dicing property was evaluated according to the following criteria. ◎ and 〇 were considered acceptable. (Evaluation) ◎: No burrs of 5 μm or more were observed from the cross-section. 〇: Burrs of 5 μm or more and less than 10 μm were observed from the cross-section. ▲: Burrs of 10 μm or more were observed from the cross-section. ×: Glass peeling from the adhesive layer or glass cracks were observed.

[0239] [Followability after active energy ray irradiation (step followability when force is applied to the unevenness and deflection of the adherend surface of the adhesive sheet after UV irradiation)] The adhesive sheets obtained in the examples and comparative examples were cut into 5 cm × 5 cm to make test pieces. Next, one release sheet of the test piece was peeled off and press-bonded at a pressure of 0.05 MPa for 10 seconds at the center of a 7 cm × 7 cm release liner with a thickness of 50 μm at a temperature environment of 23°C and bonded. After leaving the above adherend to stand in a temperature environment of 23°C for 60 minutes, it was irradiated with ultraviolet rays with an intensity of 100 mW / cm2 for 10 seconds using an electrodeless lamp (fusion lamp H bulb). After leaving the above adherend after ultraviolet ray irradiation to stand in a temperature environment of 23°C for 10 minutes, it was press-molded for 10 seconds under a pressure of 0.5 MPa using a hot press device heated to 80°C. The ratio of the thickness change of the adhesive sheet after hot pressing to the thickness of the adhesive sheet before hot pressing (thickness of the adhesive sheet after hot pressing / thickness of the adhesive sheet before hot pressing) was evaluated according to the following criteria. (Reference) ○: The ratio of the thickness of the adhesive sheet after heat pressing to the thickness of the adhesive sheet before heat pressing was less than 90%. ×: The ratio of the thickness of the adhesive sheet after standing to the thickness of the adhesive sheet before standing was 90% or more and less than 100% (no change).

[0240] The evaluation results are shown in the following table.

[0241] [Table 1]

[0242] [Table 2]

[0243] The adhesive sheets of Examples 1 to 5 in which the content of the filler (D) was within a predetermined range had good followability after active energy ray irradiation and good dicing suitability. On the other hand, for the adhesive sheet of Comparative Example 1 that did not contain the filler (D) and the adhesive sheet of Comparative Example 2 in which the content of the filler (D) exceeded the predetermined range, generation of burrs and peeling of the adhesive layer from the adherend were confirmed after dicing. Furthermore, the adhesive sheet of Comparative Example 3 that did not simultaneously contain the photocurable resin (A) having a polymerizable functional group other than the polymerizable unsaturated double bond, the thermoplastic resin (B) having a polymerizable functional group other than the polymerizable unsaturated double bond, and the photoinitiator (C) had poor followability after active energy ray irradiation.

[0244] The adhesive sheets obtained in the examples were each cut into a size of 50 mm in width × 50 mm in length and used as test samples, and the dispersibility of the filler (D) in the sheet was evaluated when observed with an optical microscope. In the adhesive sheets obtained in the examples, the number of aggregates derived from the filler (D) exceeding 1000 μm was less than 1, and the dispersibility of the filler (D) in the adhesive sheet was good. On the other hand, as a reference example, when preparing the adhesive solutions in Examples 1 to 5, a solvent-free liquid adhesive without adding methyl ethyl ketone was used. After heating the above liquid adhesive to 100 °C, it was directly dropped onto the release liner B (one side of a polyethylene terephthalate film with a thickness of 38 μm was subjected to a release treatment with a silicone compound), covered with a release liner from above, and the liquid adhesive was crushed until it had a thickness of 450 μm to produce an adhesive sheet. When the dispersibility of the adhesive sheet was evaluated in the same manner, 3 or more aggregates derived from the filler (D) exceeding 1000 μm were confirmed, and the dispersibility of the filler (D) was inferior compared to the adhesive sheets obtained in the examples.

Claims

1. A photocurable resin (A) having a polymerizable functional group other than a polymerizable unsaturated double bond, A thermoplastic resin (B) having a polymerizable functional group other than a polymerizable unsaturated double bond, A photoinitiator (C), A filler (D), An adhesive layer containing the above is provided, The photocurable resin (A) has a photo-cationic polymerizable and / or photo-anionic polymerizable functional group, The thermoplastic resin (B) is a urethane resin obtained by reacting a polyol and a polyisocyanate, The polyol is at least one selected from the group consisting of polyester polyol, polycarbonate polyol, and polyether polyol, An adhesive sheet, wherein the content of the filler (D) in the adhesive layer is 5% by mass or more and 45% by mass or less.

2. The adhesive sheet according to claim 1, wherein the average particle size of the filler (D) is 0.5 μm or more and 100 μm or less.

3. The adhesive sheet according to claim 1 or 2, containing at least one of calcium carbonate particles and silica particles as the filler (D).

4. The adhesive sheet according to any one of claims 1 to 3, wherein the thickness of the adhesive layer is 10 μm or more and 3000 μm or less.

5. The adhesive sheet according to any one of claims 1 to 4, wherein the filler (D) is dispersed in the adhesive layer.

6. The adhesive sheet according to any one of claims 1 to 5, wherein the thermoplastic resin (B) has at least one polymerizable functional group selected from the group consisting of an isocyanate group, a hydroxyl group, an oxetanyl group, and an epoxy group.

7. The adhesive sheet according to any one of claims 1 to 6, wherein the photoinitiator (C) is a photo-cationic polymerization initiator.

8. The adhesive sheet according to any one of claims 1 to 7, which is used for dicing processing.

9. The adhesive sheet according to claims 1 to 8, characterized in that the photocurable resin (A) and the thermoplastic resin (B) react with each other.

10. The adhesive sheet according to claims 1 to 9, wherein the photo-cationic polymerizable compound has at least one photo-cationic polymerizable functional group selected from the group consisting of one or more epoxy groups, oxetanyl groups, hydroxyl groups, vinyl ether groups, episulfide groups, ethyleneimine groups, and oxazoline groups in one molecule.

11. A laminate comprising the adhesive sheet according to any one of claims 1 to 10, a first member bonded to the first main surface of the adhesive sheet, and a second member bonded to the second main surface of the adhesive sheet.

12. The laminate according to claim 11, which is used in an image display device.

13. A method for manufacturing a laminate using the adhesive sheet according to any one of claims 1 to 10, comprising: Step [1] of bonding a first member to the first main surface of the adhesive sheet; Step [2] of bonding a second member to the second main surface of the adhesive sheet; Step [3] of curing the adhesive layer of the adhesive sheet, and having: A method for manufacturing a laminate, further comprising a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays before step [1] or between step [1] and step [2].

14. A method for manufacturing an article using the adhesive sheet according to any one of claims 1 to 10, comprising: Step [1] of bonding a first member to the first main surface of the adhesive sheet; Step [2] of bonding a second member to the second main surface of the adhesive sheet; Step [3] of curing the adhesive layer of the adhesive sheet to form a laminate; Step [4] of cutting the laminate into a plurality of articles for individual pieces; And having: A method for manufacturing an article, further comprising a step of irradiating the first main surface or the second main surface of the adhesive sheet with active energy rays before step [1] or between step [1] and step [2].

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